CN112567676A

CN112567676A - Method for operating terminal and base station in wireless communication system supporting NB-IOT and supported apparatus

Info

Publication number: CN112567676A
Application number: CN201980053733.2A
Authority: CN
Inventors: 黄升溪; 朴昶焕; 安俊基
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2018-08-09
Filing date: 2019-08-09
Publication date: 2021-03-26
Anticipated expiration: 2039-08-09
Also published as: WO2020032739A1; US20210329591A1; CN112567676B; DE112019004010T5; US11956754B2

Abstract

Disclosed in the present invention is a method for operating a terminal and a base station in a wireless communication system supporting narrowband internet of things (NB-IoT) and an apparatus supporting the same. According to one embodiment applicable to the present invention, a terminal determines a time interval for receiving NRSs in a non-anchor carrier used for paging purposes, and receives NRSs in the time interval. The time interval may be determined based on a specific PO among a plurality of POs related to the terminal.

Description

Method for operating terminal and base station in wireless communication system supporting NB-IOT and supported apparatus

Technical Field

The present disclosure relates to a wireless communication system supporting narrowband internet of things (NB-IoT), and more particularly, to an operation method for a terminal and a base station in a wireless communication system and an apparatus supporting the same.

Background

In general, wireless communication systems are being developed to variously cover a wide range to provide communication services such as audio communication services, data communication services, and the like. Wireless communication is a multiple-access system capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). For example, the multiple-access system may include one of a CDMA (code division multiple access) system, an FDMA (frequency division multiple access) system, a TDMA (time division multiple access) system, an OFDMA (orthogonal frequency division multiple access) system, an SC-FDMA (single carrier frequency division multiple access) system, and the like.

Furthermore, as more and more communication devices have required higher communication capacity, mobile broadband communication technologies have been introduced that are enhanced over existing Radio Access Technologies (RATs). Further, not only large-scale Machine Type Communication (MTC) capable of providing various services anytime and anywhere by connecting many devices or things to each other, but also a communication system considering a service/User Equipment (UE) sensitive to reliability and latency has been introduced.

As described above, enhanced mobile broadband communication, large-scale MTC, ultra-reliable low-latency communication (URLLC), and the like have been introduced.

Disclosure of Invention

Technical problem

An object of the present disclosure is to provide an operation method of a terminal (user equipment) and a base station in a wireless communication system for supporting narrowband internet of things (NB-IoT) and an apparatus supporting the same.

It will be appreciated by those skilled in the art that the objects that can be achieved with the present disclosure are not limited to the objects that have been particularly described hereinabove, and that the above and other objects that can be achieved with the present disclosure will be more clearly understood from the following detailed description.

Technical scheme

The present disclosure provides an operation method of a User Equipment (UE) and a base station in a wireless communication system for supporting narrowband internet of things (NB-IoT) and an apparatus supporting the same.

In one implementation of the present disclosure, a method of operating a UE in a wireless communication system for supporting NB-IoT is provided. The method can comprise the following steps: determining a time period for receiving a Narrowband Reference Signal (NRS) on a non-anchor carrier for paging; and receiving the NRS during the time period. The time period may be determined based on a specific Paging Occasion (PO) among a plurality of POs related to the UE.

The specific PO may be a PO having an odd subframe number among the plurality of POs.

The specific PO may be a PO having an odd subframe number and an even System Frame Number (SFN) among the plurality of POs.

The specific PO may be a PO having an even subframe number and an odd SFN among the plurality of POs.

The specific PO may be a PO in which a remainder of division of S by R is equal to a remainder of division of Q +1 by 2 among the plurality of POs, where S is an SFN of the PO, R is a value pre-configured by a higher layer signal, and Q is a subframe number of the PO.

R may be determined based on a ratio between the number of frames and the number of POs.

In the case where the number of POs in one frame is greater than or equal to 2, R may be 2, and in the case where the number of POs in one frame is less than 2, R may be 1.

The specific PO may be a PO in which a remainder of division of S by R is equal to a remainder of division of Q + a by 2 among the plurality of POs, where S is an SFN of the PO, R is a value pre-configured by a higher layer signal, Q is a subframe number of the PO, and a is 0 or 1.

In case that the number of POs in one frame is less than 1, a may be determined as 1, and in case that the number of POs in one frame is greater than 1, a may be determined as 0 or 1 based on the SFN of the specific PO.

The specific PO may be a PO of subframe number 9 among the plurality of POs.

Reception of the NRS within the time period may be determined independently of page transmission.

In another implementation of the present disclosure, a UE in a wireless communication system supporting NB-IoT is provided. The UE may include: at least one Radio Frequency (RF) module; at least one processor; and at least one memory operatively connected to the at least one processor and configured to store instructions executable by the at least one processor to perform certain operations. The specific operations may include: determining a time period for receiving NRS on a non-anchor carrier for paging; and receiving the NRS during the time period. The time period may be determined based on a specific PO among a plurality of POs related to the UE, and the reception of the NRS within the time period may be independent of the presence of the paging transmission.

The specific PO may be a PO in which a remainder of division of S by R is equal to a remainder of division of Q +1 by 2 among the POs, S is an SFN of the PO, R is a value pre-configured by a higher layer signal, and Q is a subframe number of the PO.

The UE may communicate with at least one of a mobile terminal, a network, or an autonomous driving vehicle other than the vehicle that includes the UE.

In another aspect of the disclosure, a base station for transmitting downlink signals in an NB-IoT enabled wireless communication system is provided. The base station may include: at least one RF module; at least one processor; and at least one memory operatively connected to the at least one processor and configured to store instructions executable by the at least one processor to perform certain operations. The specific operation may include transmitting NRS to the UE on a non-anchor carrier for paging for a specific time period. The specific time period may be determined based on a specific PO among a plurality of POs related to the UE, and the transmission of the NRS within the specific time period may be independent of the presence of the paging transmission.

The specific PO may be a PO in which a remainder of S divided by R is equal to a remainder of Q +1 divided by 2 among the POs, where S is an SFN of the PO, R is a value pre-configured by a higher layer signal, and Q is a subframe number of the PO.

It should be understood by those skilled in the art that the above-described implementations of the present disclosure are only part of the implementations of the present disclosure, and various modifications and alternatives can be developed in light of the following technical features of the present disclosure.

Advantageous effects

As is apparent from the above description, the present disclosure has the following effects.

According to the present disclosure, a User Equipment (UE) may assume that at least one of a Narrowband Reference Signal (NRS) and a cell-specific reference signal (CRS) is transmitted on a non-anchor carrier (e.g., a non-anchor carrier managed for paging), and then receive the corresponding signal. Further, the base station may transmit a corresponding reference signal to the UE on a non-anchor carrier based on the UE's assumption.

According to the above configuration, the UE may perform monitoring (e.g., Radio Resource Management (RRM) measurements) on the non-anchor carriers based on the corresponding reference signals.

According to the above configuration, UE operations (e.g., RRM measurements, etc.) not supported by the latest standard specifications may be additionally supported.

According to the above configuration, the UE can assume and receive a reference signal on a Paging Occasion (PO) among a plurality of POs, thereby reducing monitoring overhead of the UE.

It will be appreciated by those skilled in the art that the effects that can be achieved with the present disclosure are not limited to those that have been particularly described hereinabove, and other advantages of the present disclosure will be more clearly understood from the following detailed description.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate implementation of the disclosure and together with the description serve to explain the principles of the disclosure. Technical features of the present disclosure are not limited to specific drawings, and features shown in the drawings are combined to construct a new implementation. Reference numerals of the drawings refer to structural elements.

Fig. 1 illustrates an example of a third generation partnership project (3GPP) Long Term Evolution (LTE) system architecture.

Fig. 2 illustrates an example of a 3GPP New Radio (NR) system architecture.

Fig. 3 illustrates physical channels and a general signal transmission method using the physical channels, which are applicable to implementations of the present disclosure.

Fig. 4 is a diagram illustrating a structure of a radio frame in an LTE system to which implementations of the present disclosure are applicable.

Fig. 5 is a diagram illustrating a structure of a slot in an LTE system to which implementations of the present disclosure are applicable.

Fig. 6 is a diagram illustrating a structure of a Downlink (DL) subframe in an LTE system to which implementations of the present disclosure are applicable.

Fig. 7 is a diagram illustrating a structure of an Uplink (UL) subframe in an LTE system to which implementations of the present disclosure are applicable.

Fig. 8 is a diagram illustrating a structure of a radio frame in an NR system to which the implementation of the present disclosure is applicable.

Fig. 9 is a diagram illustrating a structure of a slot in an NR system to which implementations of the present disclosure are applicable.

Fig. 10 is a diagram illustrating a structure of a self-contained slot in an NR system to which an implementation of the present disclosure is applicable.

Fig. 11 illustrates an example of narrowband operation and frequency diversity.

Fig. 12 illustrates physical channels available in Machine Type Communication (MTC) and a general signal transmission method using the same.

Fig. 13 illustrates an example of system information transmission in MTC.

Fig. 14 illustrates an example of scheduling for each of MTC and legacy LTE.

Fig. 15 and 16 illustrate examples of narrowband internet of things (NB-IoT) frame structures depending on subcarrier spacing.

Fig. 17 illustrates an example of a resource grid for NB-IoT UL.

Fig. 18 illustrates the operational modes supported in an NB-IoT system.

Fig. 19 illustrates physical channels available in an NB-IoT and a general signaling method using the physical channels.

Fig. 20 illustrates an Initial Access (IA) procedure applicable to an NB-IoT system.

Fig. 21 illustrates a random access procedure applicable to an NB-IoT system.

Fig. 22 illustrates an example of a Discontinuous Reception (DRX) mode in an idle and/or inactive state.

Fig. 23 illustrates an example of DRX configuration and indication procedures for NB-IoT UEs.

Fig. 24 is a diagram schematically illustrating a cell-specific reference signal (CRS) pattern applicable to the present disclosure.

Fig. 25 is a diagram schematically illustrating a Narrowband Reference Signal (NRS) pattern applicable to the present disclosure.

Fig. 26 is a flowchart schematically illustrating an operation method of a base station applicable to the present disclosure.

Fig. 27 is a flowchart schematically illustrating an operation method of a User Equipment (UE) applicable to the present disclosure.

Fig. 28 is a diagram schematically illustrating an NRS transmission and reception method according to an implementation of the present disclosure.

Fig. 29 is a diagram schematically illustrating an NRS transmission and reception method according to an implementation of the present disclosure.

Fig. 30 is a flowchart schematically illustrating a method for a UE to receive NRS according to an implementation of the present disclosure.

Fig. 31 is a flowchart schematically illustrating an NRS transmission and reception method between a UE and a base station according to an implementation of the present disclosure.

Fig. 32 illustrates a communication system applicable to the present disclosure.

Fig. 33 illustrates a wireless device applicable to the present disclosure.

Fig. 34 illustrates another example of a wireless device applicable to the present disclosure.

Fig. 35 illustrates a handheld device applicable to the present disclosure.

Fig. 36 illustrates a vehicle or autonomous driving vehicle applicable to the present disclosure.

Fig. 37 illustrates a carrier applicable to the present disclosure.

Detailed Description

The following implementations are combinations of specific forms of elements and features of the present disclosure. These elements or features may be considered optional unless otherwise mentioned. Each element or feature may be practiced without being combined with other elements or features. Further, implementations of the present disclosure may be constructed by combining some of these elements and/or features. The order of operations described in the implementations of the present disclosure may be rearranged. Some configurations or elements of any one implementation may be included in another implementation or replaced with corresponding configurations or features of another implementation.

In the following description and the accompanying drawings, well-known processes or steps that may obscure the subject matter of the present disclosure will be omitted. In addition, processes or steps that can be understood by those skilled in the art will also be omitted.

Throughout the specification, when a certain portion is said to "include or contain" a certain component, this may be interpreted as meaning that other components are not excluded unless otherwise specified, and other components may be further included. The terms "unit", "device or" and "module" described in the present specification may mean a unit for processing at least one function or operation, which may be implemented by hardware, software, or a combination thereof. The words "a" or "an", "the" and words of description "and" the "may be used to encompass both the singular and the plural, unless the context of the disclosure (especially the context of the appended claims) clearly dictates otherwise.

Implementations of the present disclosure will be described based on a data transmission and reception relationship between a mobile station and a base station. A base station may refer to a terminal node of a network configured to communicate directly with a mobile station. In some cases, certain operations described in this document as being performed by a base station may be performed by an upper node of the base station.

In a network including a plurality of network nodes including a base station, various operations performed for communication with a mobile station may be performed by the base station or other network nodes other than the base station. In this document, the term "base station" may be interchanged with fixed stations, Node bs, evolved nodeb (enb), enode bs (gNB), Advanced Base Stations (ABS), access points, etc.

The term "terminal" may be interchanged with User Equipment (UE), Mobile Station (MS), Subscriber Station (SS), mobile subscriber station (MSs), mobile terminal, Advanced Mobile Station (AMS), etc.

In addition, the transmitting end refers to a fixed node and/or a mobile node that transmits data or voice service, and the receiving end refers to a fixed node and/or a mobile node that receives data or voice service. In the uplink, a mobile station and a base station may correspond to a transmitting end and a receiving end, respectively. In downlink, a mobile station and a base station may correspond to a receiving end and a transmitting end, respectively.

Implementations of the present disclosure may be supported by standard specifications published for at least one of the wireless access systems, including: institute of Electrical and Electronics Engineers (IEEE)802.xx, third generation partnership project (3GPP), 3GPP Long Term Evolution (LTE), 3GPP fifth generation (5G) New Radio (NR), or 3GPP 2. In particular, implementations of the present disclosure may be supported by the following standard specifications: 3GPP TS 36.211, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS 36.321, 3GPP TS 36.331, 3GPP TS 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.321, and 3GPP TS 38.331. That is, steps or portions of implementations of the present disclosure, which are not described to clearly disclose the technical idea of the present disclosure, may be illustrated by the above standard specifications. All terms used in implementations of the present disclosure may also be supported by standard specifications.

Reference will now be made in detail to implementations of the present disclosure with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to illustrate exemplary implementations of the present disclosure, and is not intended to show the only implementations that can be implemented according to the present disclosure.

The following techniques may be applied to various wireless access systems such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and the like.

Although the present disclosure is described based on a 3GPP communication system (e.g., LTE-A, NR, etc.) for clarity of description, the spirit of the present disclosure is not limited thereto. LTE refers to technology beyond the 3GPP Technical Specification (TS)36.xxx release 8. Specifically, LTE technology beyond 3gpp ts36.xxx release 10 is referred to as LTE-a, while LTE technology beyond 3gpp ts36.xxx release 13 is referred to as LTE-a pro. 3gpp nr refers to techniques beyond 3gpp ts 38.xxx version 15. LTE/NR may be referred to as a "3 GPP system". Here, "xxx" refers to the standard specification number. LTE/NR may be collectively referred to as a "3 GPP system". Details of the background, terms, abbreviations, etc. used herein may be found in documents published prior to the present disclosure. For example, the following documents may be referred to.

3GPP LTE

-36.211:Physical channels and modulation

-36.212:Multiplexing and channel coding

-36.213:Physical layer procedures

-36.300:Overall description

-36.331:Radio Resource Control(RRC)

3GPP NR

-38.211:Physical channels and modulation

-38.212:Multiplexing and channel coding

-38.213:Physical layer procedures for control

-38.214:Physical layer procedures for data

-38.300:NR and NG-RAN Overall Description

-38.331:Radio Resource Control(RRC)protocol specification

1. System architecture

Fig. 1 illustrates an example of a 3GPP LTE system architecture.

The wireless communication system may be referred to as an evolved UMTS terrestrial radio Access network (E-UTRAN) or a Long Term Evolution (LTE)/LTE-A system. Referring to fig. 1, the E-UTRAN includes at least one base station providing a UE 10 with a control plane and a user plane. The UE may be fixed or mobile. The UE may be referred to as another term such as "Mobile Station (MS)", "User Terminal (UT)", "Subscriber Station (SS)", "Mobile Terminal (MT)" or "wireless device". In general, a base station may be a fixed station that communicates with the UEs. A base station may be referred to as another term such as "evolved node b (enb)", "general node b (gnb)", "Base Transceiver System (BTS)" or "Access Point (AP)". The base stations may be interconnected by an X2 interface. The base station may be connected to an Evolved Packet Core (EPC) through an S1 interface. More specifically, the base station may be connected to a Mobility Management Entity (MME) through S1-MME and may be connected to a serving gateway (S-GW) through S1-U. The EPC includes an MME, an S-GW, and a packet data network gateway (P-GW). Radio interface protocol layers between the UE and the network may be classified into layer 1(L1), layer 2(L2), and layer 3(L3) based on three lower layers of an Open System Interconnection (OSI) model well known in the communication system. The Physical (PHY) layer belonging to L1 provides a transfer service via a physical channel. A Radio Resource Control (RRC) layer belonging to L3 controls radio resources between the UE and the network. For this, the base station and the UE may exchange RRC messages through the RRC layer.

Fig. 2 illustrates an example of a 3gpp nr system architecture.

Referring to fig. 2, the NG-RAN includes gnbs, each of which provides the NG-RA user plane (e.g., new AS sublayer/PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminals to the UE. The gnbs are interconnected by an Xn interface. The gNB is connected to the NGC through the NG interface. More specifically, the gNB is connected to access and mobility management functions through an N2 interface and to User Plane Functions (UPFs) through an N3 interface.

Overview of 2.3 GPP systems

2.1. Physical channel and general signal transmission and reception

In a wireless access system, a UE receives information from a base station in a Downlink (DL) and transmits information to the base station in an Uplink (UL). Information transmitted and received between the UE and the base station includes general data information and various types of control information. There are many physical channels depending on the type/usage of information transmitted and received between the UE and the base station.

When the UE is powered on or enters a new cell, the UE performs an initial cell search (S11). Initial cell search involves acquisition of synchronization with a base station. Specifically, the UE synchronizes its timing with the base station by receiving a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from the base station and obtains information such as a cell Identifier (ID).

The UE may then obtain the information broadcast in the cell by receiving a Physical Broadcast Channel (PBCH) from the base station.

During initial cell search, the UE may monitor the state of a downlink reference signal (DL RS) by receiving the DL RS.

After completing the initial cell search, the UE may obtain more detailed system information by receiving a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Shared Channel (PDSCH) depending on information in the PDCCH (S12).

To complete access to the base station, the UE may perform a random access procedure (S13 to S16). To this end, the UE may transmit a preamble over a Physical Random Access Channel (PRACH) (S13) and receive a Random Access Response (RAR) for the preamble on the PDCCH and PDSCH associated therewith. The UE may transmit a Physical Uplink Shared Channel (PUSCH) based on the scheduling information in the RAR (S15). The UE may perform a contention resolution procedure by receiving a PDCCH signal and a PDSCH signal associated therewith (S16).

After completing the above procedure, the UE may perform reception of a PDCCH signal and/or a PDSCH signal (S17) and transmission of a Physical Uplink Control Channel (PUCCH) signal and a PUSCH signal (S18) as a general UL/DL signal transmission procedure.

The control information transmitted from the UE to the base station is generally referred to as Uplink Control Information (UCI). The UCI includes hybrid automatic repeat and request acknowledgement/negative acknowledgement (HARQ-ACK/NACK), Scheduling Request (SR), Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Rank Indicator (RI), and the like.

In general, UCI may be transmitted periodically over PUCCH. However, UCI (if it is necessary to simultaneously transmit control information and traffic data) may be transmitted on the PUSCH. Further, the UE may transmit UCI aperiodically over PUSCH when receiving a request/command from the network.

2.2. Radio frame structure

The LTE system supports a frame structure type1 for Frequency Division Duplex (FDD), a frame structure type 2 for Time Division Duplex (TDD), and a frame structure type 3 for a non-licensed cell (UCell). In LTE systems, up to 31 secondary cells (scells) may be aggregated with a primary cell (PCell). The following operations may be applied independently for each cell unless otherwise specified.

In multi-cell aggregation, different frame structures may be used for different cells. In addition, time resources (e.g., subframes, slots, subslots, etc.) in a frame structure may be collectively referred to as a Time Unit (TU).

Fig. 4(a) illustrates a frame structure type 1. The frame structure type1 is applicable to both full-duplex FDD systems and half-duplex FDD systems.

A DL radio frame is defined as 10 1-ms (millisecond) subframes. A subframe includes 12 or 14 symbols depending on a Cyclic Prefix (CP). In case of the normal CP, one subframe includes 14 symbols, and in case of the extended CP, one subframe includes 12 symbols.

Depending on the multiple access scheme, a symbol may refer to an OFDM (A) symbol or an SC-FDM (A) symbol. For example, a symbol may refer to an ofdm (a) symbol in DL and an SC-fdm (a) symbol in UL. The ofdm (a) symbol may be referred to as a cyclic prefix-ofdma (a) (CP-ofdm (a)) symbol, and the SC-fmd (a) symbol may be referred to as a discrete fourier transform-spread-ofdm (a) (DFT-s-ofdm (a)) symbol.

One subframe may be defined as one or more slots according to subcarrier spacing (SCS) as follows.

When SCS is 7.5kHz or 15kHz, subframe # i is defined as two 0.5-ms slots: slot #2i and slot #2i +1(i ═ 0 to 9).

When SCS is 1.25kHz, subframe # i is defined as one 1-ms slot, i.e. slot #2 i.

When SCS is 15kHz, subframe # i may be defined as six sub-slots as shown in table a 1.

Table 1 shows a sub-slot configuration in one subframe (normal CP).

[ Table 1]

Fig. 4(b) illustrates a frame structure type 2. The frame structure type 2 is applied to the TDD system. Frame structure type 2 includes two half frames. A half frame includes 4 (or 5) normal subframes and 1 (or 0) special subframes. The normal subframe is used for UL or DL according to UL-DL configuration. One subframe includes two slots.

Table 2 shows a subframe configuration in a radio frame depending on the UL-DL configuration.

[ Table 2]

In table 2, D denotes a DL subframe, U denotes a UL subframe, and S denotes a special subframe. The special subframe includes a downlink pilot time slot (DwPTS), a Guard Period (GP), and an uplink pilot time slot (UpPTS). The DwPTS is used for initial cell search, synchronization, or channel estimation at the UE. UpPTS is used for channel estimation at the base station and UL transmission synchronization acquisition at the UE. The GP is a period for canceling UL interference caused by multipath delay of a DL signal between DL and UL.

Table 3 shows a special subframe configuration.

[ Table 3]

In table 3, X is configured by higher layer signaling (e.g., Radio Resource Control (RRC) signaling) or is given as 0.

Referring to fig. 4, one slot includes a plurality of OFDM symbols in a time domain and a plurality of Resource Blocks (RBs) in a frequency domain. A symbol may refer to a symbol duration. The slot structure may be formed by including N^DL/UL _RB×N^RB _scSub-carriers and N^DL/UL _symbA resource grid representation of individual symbols. N is a radical of^DL _RBDenotes the number of RBs in the DL slot, and N^UL _RBIndicating the number of RBs in the UL slot. N is a radical of^DL _RBAnd N^UL _RBDepending on the DL bandwidth and the UL bandwidth, respectively. N is a radical of^DL _symbDenotes the number of symbols in the DL slot, and N^UL _symbIndicating the number of symbols in the UL slot. N is a radical of^RB _scIndicating the number of subcarriers in one RB. Time slotThe number of symbols in (1) may be different depending on the SCS and CP length (see table 1). For example, one slot includes 7 symbols in case of a normal CP and 6 symbols in case of an extended CP.

One RB is defined as N in the time domain^DL/UL _symb(e.g., 7) consecutive symbols and N in the frequency domain^RB _sc(e.g., 12) consecutive subcarriers. The RB may be a Physical Resource Block (PRB) or a Virtual Resource Block (VRB), and the PRB may be mapped to the VRB in a one-to-one correspondence. Two RBs each located in one of two slots of a subframe may be referred to as an RB pair. The two RBs in an RB pair may have the same RB number (or RB index). A resource composed of one symbol and one subcarrier is called a Resource Element (RE) or a tone. Each RE in the resource grid may be uniquely identified by an index pair (k, l) in the slot, where k is from 0 to N^DL/UL _RB×N^RB _sc-a frequency domain index of 1, and l is from 0 to N^DL/UL _symb-a time domain index of 1.

Fig. 6 is a diagram illustrating a structure of a DL subframe in an LTE system to which implementations of the present disclosure are applicable.

Referring to fig. 6, up to three (or four) ofdm (a) symbols at the beginning of the first slot of the subframe correspond to a control region allocated with a DL control channel. The remaining ofdm (a) symbols correspond to a data region to which the PDSCH is allocated, and the basic resource unit of the data region is an RB. The DL control channel includes a Physical Control Format Indicator Channel (PCFICH), a PDCCH, a physical hybrid ARQ indicator channel (PHICH), and the like.

The PCFICH is transmitted in the first OFDM symbol of the subframe, carrying information on the number of OFDM symbols used to transmit control channels in the subframe (i.e., the size of the control region). The PHICH is a response channel for UL transmission, and carries HARQ-ACK/NACK signals. Control information transmitted over the PDCCH is referred to as Downlink Control Information (DCI). The DCI includes UL resource allocation information, DL resource control information, or UL Transmit (TX) power control commands for any UE group.

Fig. 7 is a diagram illustrating a structure of a UL subframe in an LTE system to which implementations of the present disclosure are applicable.

Referring to fig. 7, one subframe 600 includes two 0.5-ms slots 601. Each slot includes a plurality of symbols 602, each symbol corresponding to an SC-FDMA symbol. An RB 603 is a resource allocation unit, which is defined by 12 subcarriers in the frequency domain and one slot in the time domain.

The UL subframe is generally divided into a data region 604 and a control region 605. The data region refers to a communication resource used by each UE to transmit data such as voice, packet, etc., and includes a PUSCH. The control region refers to a communication resource used by each UE to transmit an UL control signal, for example, a report on DL channel quality, ACK/NACK for DL signal reception, UL scheduling request, etc., and includes a PUCCH.

A Sounding Reference Signal (SRS) is transmitted in a last SC-FDMA symbol of a subframe in a time domain.

UL transmission and DL transmission in the NR system are based on the frame shown in fig. 8. One radio frame has a duration of 10ms, defined as two 5-ms half-frames. One half frame is defined as five 1-ms subframes. One subframe is divided into one or more slots, and the number of slots in one subframe depends on the SCS. Each slot includes 12 or 14 ofdm (a) symbols depending on the CP. Each slot includes 14 symbols in the case of a normal CP and 12 symbols in the case of an extended CP. Herein, the symbol may include an OFDM symbol (or CP-OFDM symbol) and/or an SC-FDMA symbol (or DFT-s-OFDM symbol).

Table 4 shows the number of symbols in each slot, the number of slots in each frame, and the number of slots in each subframe depending on SCS in case of normal CP. Table 5 shows the number of symbols in each slot, the number of slots in each frame, and the number of slots in each subframe depending on SCS in case of the extended CP.

[ Table 4]

[ Table 5]

In the above table, N^slot _symbIndicating the number of symbols in the slot, N^frame,μ _slotIndicates the number of slots in a frame, and N^subframe,μ _slotIndicating the number of slots in a subframe.

In the NR system to which the present disclosure is applicable, different ofdm (a) parameter sets (e.g., SCS, CP length, etc.) may be configured for a plurality of cells aggregated for one UE. Accordingly, the (absolute) duration of time resources (e.g., SF, slot, or TTI) including the same number of symbols may be different between aggregated cells (for convenience of description, such time resources are referred to as TUs).

One slot includes a plurality of symbols in the time domain. For example, one slot includes 7 symbols in case of a normal CP and 6 symbols in case of an extended CP.

A carrier includes a plurality of subcarriers in the frequency domain. An RB is defined as a plurality of (e.g., 12) consecutive subcarriers in the frequency domain.

A bandwidth part (BWP) is defined as a plurality of consecutive (P) RBs in the frequency domain. BWP may correspond to one parameter set (e.g., SCS, CP length, etc.).

The carrier may include up to N (e.g., 5) BWPs. Data communication may be in active BWP and only one BWP may be activated for one UE. Each element in the resource grid is referred to as an RE. One complex symbol may be mapped to an RE.

In fig. 10, a shaded region (e.g., symbol index ═ 0) represents a DL control region, and a black region (e.g., symbol index ═ 13) represents a UL control region. The remaining region (e.g., symbol index ═ 1 to 12) may be used for DL or UL data transmission.

Based on this structure, the base station and the UE can sequentially perform DL transmission and UL transmission in one slot. That is, the base station and the UE may exchange not only DL data but also UL ACK/NACK for the DL data in the one slot. Therefore, this structure can reduce the time required until data retransmission when a data transmission error occurs, thereby minimizing the delay of the final data transfer.

In such a self-contained slot structure, a time gap with a predetermined duration is required to allow the base station and the UE to switch from a transmission mode to a reception mode, and vice versa. For this, some OFDM symbols at the time of switching from DL to UL may be set as GP in the self-contained slot structure.

Although it has been described above that the self-contained slot structure includes the DL control region and the UL control region, these control regions may be selectively included in the self-contained slot structure. In other words, the self-contained slot structure according to the present disclosure may include a DL control region or an UL control region as shown in fig. 10, and include both the DL control region and the UL control region.

In addition, the order of the regions in one slot may vary in some implementations. For example, one slot may be configured in the following order: DL control region/DL data region/UL control region/UL data region, or UL control region/UL data region/DL control region/DL data region.

The PDCCH may be transmitted in a DL control region and the PDSCH may be transmitted in a DL data region. The PUCCH may be transmitted in the UL control region and the PUSCH may be transmitted in the UL data region.

The PDCCH may carry DCI, e.g., DL data scheduling information, UL data scheduling information, etc. The PUCCH may carry UCI, e.g., ACK/NACK for DL data, Channel State Information (CSI), SR, etc.

The PDSCH may carry DL data (e.g., DL shared channel transport block (DL-SCH TB)). Modulation schemes such as Quadrature Phase Shift Keying (QPSK), 16-ary quadrature amplitude modulation (16QAM), 64QAM, or 256 QAM. The TBs are encoded into codewords. The PDSCH may carry up to two codewords. Scrambling and modulation mapping are performed on a codeword basis, and modulation symbols generated from each codeword are mapped to one or more layers (layer mapping). Each layer is mapped to resources together with a demodulation reference signal (DMRS) created as an OFDM symbol signal and then transmitted through a corresponding antenna port.

The PDCCH may carry DCI, and a QPSK modulation scheme is applied to the DCI. One PDCCH includes 1, 2, 4, 8, or 16 Control Channel Elements (CCEs) depending on an Aggregation Level (AL). One CCE includes 6 Resource Element Groups (REGs). One REG is defined as one OFDM symbol and one (P) RB.

3. Machine Type Communication (MTC)

Machine Type Communication (MTC) refers to a communication technology adopted by the third generation partnership project (3GPP) to meet internet of things (IOT) service requirements. Since MTC does not require high throughput, it can be used as a machine-to-machine (M2M) and internet of things (IoT) application.

MTC may be implemented to meet the following requirements: (i) low cost and low complexity; (ii) and enhancing the coverage: (iii) and the power consumption is low.

MTC was introduced in 3GPP release 10. Hereinafter, MTC functions added in each 3GPP release will be described.

MTC load control was introduced in 3GPP releases 10 and 11.

The load control method prevents the IoT (or M2M) device from suddenly placing a heavy burden on the base station.

Specifically, according to release 10, when a load occurs, the base station may disconnect from the IoT device to control the load. According to release 11, the base station may prevent the UE from attempting to establish a connection by notifying the UE via a broadcast such as SIB14 that access will become available.

In release 12, a feature of low cost MTC is added, for which UE class 0 is newly defined. The UE category indicates the amount of data that the UE can process using the communication modem.

In particular, UEs belonging to UE class 0 may use a reduced peak data rate, half-duplex operation with relaxed RF requirements, and a single receive antenna, thereby reducing the baseband and RF complexity of the UE.

In release 13, enhanced mtc (emtc) was introduced. In eMTC, the UE operates with a bandwidth of 1.08MHz, which is the minimum frequency bandwidth supported by the conventional LTE, thereby further reducing cost and power consumption.

Although the following description refers to eMTC, the description is equally applicable to MTC, 5G (or NR) MTC, etc. For ease of illustration, all types of MTC are commonly referred to as "MTC".

In the following description, MTC may be referred to as another term such as "eMTC", "LTE-M1/M2", "reduced bandwidth low complexity/coverage enhancement (BL/CE)", "non-BLUE (in enhanced coverage)", "NRMTC", or K-enhanced BL/CE ". Furthermore, the term "MTC" may be replaced with terms defined in future 3GPP standards.

General features of MTC

(1) MTC operates only in a specific system bandwidth (or channel bandwidth).

The specific system bandwidth may use 6 RBs of the conventional LTE as shown in table 6 below and be defined by considering the frequency range and subcarrier spacing (SCS) shown in tables 7 to 9. The particular system bandwidth may be referred to as a Narrowband (NB). Here, the legacy LTE may include contents other than MTC described in the 3GPP standard. In NR, MTC may use RBs corresponding to the minimum system bandwidth in tables 8 and 9 as in conventional LTE. Alternatively, MTC may operate in at least one BWP or in a specific frequency band of BWPs.

[ Table 6]

Table 7 shows the Frequency Ranges (FR) defined for NR.

[ Table 7]

Frequency range designation	Corresponding frequency range
		FR1	450MHz-6000MHz
FR2	24250MHz-52600MHz

Table 8 shows the maximum transmission bandwidth configuration (NRB) for the channel bandwidth and SCS in NR FR 1.

[ Table 8]

Table 9 shows the maximum transmission bandwidth configuration (NRB) for the channel bandwidth and SCS in NRFR 2.

[ Table 9]

Hereinafter, MTC Narrowband (NB) will be described in detail.

MTC follows narrowband operation to transmit and receive physical channels and signals, and the maximum channel bandwidth is reduced to 1.08MHz or 6(LTE) RBs.

The narrow bands may be used as reference units for allocating resources for some downlink and uplink channels, and the physical location of each narrow band in the frequency domain may vary depending on the system bandwidth.

The 1.08MHz bandwidth for MTC is defined such that MTC UEs follow the same cell search and random access procedures as legacy UEs.

A cell having a larger bandwidth (e.g., 10MHz) may support MTC, but physical channels and signals transmitted/received in MTC are always limited to 1.08 MHz.

A legacy LTE system, an NR system, a 5G system, etc. may support a larger bandwidth.

The narrow band is defined in the frequency domain as 6 non-overlapping consecutive physical RBs.

If it is not

The wideband is defined in the frequency domain as four non-overlapping narrow bands. If it is not

Then

And a single broadband router

A plurality of non-overlapping narrow bands.

For example, in the case of a 10MHz channel, 8 non-overlapping narrow bands are defined.

Fig. 11 illustrates an example of narrowband operation and frequency diversity.

Specifically, fig. 11(a) illustrates an example of narrowband operation, and fig. 11(b) illustrates an example of repetition with RF retuning.

Hereinafter, frequency diversity by RF retuning will be described with reference to fig. 11 (b).

MTC supports limited frequency, spatial and time diversity due to narrowband RF, single antenna and limited mobility. Frequency hopping between different narrow bands is supported by RF retuning in order to reduce the effects of fading and disruptions.

When repetition is enabled, frequency hopping is applied to different uplink and downlink physical channels.

For example, if 32 subframes are used for PDSCH transmission, the first 16 subframes may be transmitted on the first narrowband. In this case, the RF front end is retuned to another narrowband, while the remaining 16 subframes are transmitted on the second narrowband.

The MTC narrowband may be configured through system information or DCI.

(2) MTC operates in half-duplex mode and uses a limited (or reduced) maximum transmission power.

(3) MTC does not use a channel (defined in legacy LTE or NR) that should be allocated over the entire system bandwidth of the legacy LTE or NR.

For example, MTC does not use the following legacy LTE channels: PCFICH, PHICH, and PDCCH.

Therefore, since the above channels are not monitored, a new control channel MTC PDCCH (MPDCCH) is defined for MTC.

MPDCCH may occupy up to 6 RBs in the frequency domain and up to one subframe in the time domain.

MPDCCH is similar to evolved pdcch (epdcch) and supports a common search space for paging and random access.

In other words, the concept of MPDCCH is similar to that of EPDCCH used in legacy LTE.

(4) MTC uses a newly defined DCI format. For example, DCI formats 6-0A, 6-0B, 6-1A, 6-1B, 6-2, etc. may be used.

In MTC, a Physical Broadcast Channel (PBCH), a Physical Random Access Channel (PRACH), an MPDCCH, a PDSCH, a PUCCH, and a PUSCH may be repeatedly transmitted. MTC repeated transmission enables MTC channels to be decoded in a harsh environment such as a basement (i.e., when signal quality or power is low), thereby increasing the radius of a cell or supporting signal propagation effects. MTC may support a limited number of Transmission Modes (TM) capable of operating on a single layer (or a single antenna), or may support channels or Reference Signals (RSs) capable of operating on a single layer. For example, MTC may operate according to TM1, 2, 6 or 9.

(6) In MTC, HARQ retransmissions are adaptive and asynchronous and are performed based on new scheduling assignments received on MPDCCH.

(7) In MTC, PDSCH scheduling (DCI) and PDSCH transmission occur in different subframes (cross-subframe scheduling).

(8) All resource allocation information (e.g., subframe, Transport Block Size (TBS), subband index, etc.) for SIB1 decoding is determined by the Master Information Block (MIB) parameters (in MTC, no control channel is used for SIB1 decoding).

(9) All resource allocation information (e.g., subframe, TBS, subband index, etc.) used for SIB2 decoding is determined by several SIB1 parameters (in MTC, no control channel is used for SIB2 decoding).

(10) MTC supports extended Discontinuous Reception (DRX) cycles.

(11) MTC may use the same primary/secondary synchronization signal/common reference signal (PSS/SSS/CRS) as used in legacy LTE or NR. In NR, PSS/SSs is transmitted in units of SS blocks (or SS/PBCH blocks or SSBs), and tracking rs (trs) may be used for the same purpose as CRS. That is, the TRS is a cell-specific RS, and can be used for frequency/time tracking.

MTC modes of operation and grades

Hereinafter, MTC operation modes and classes will be described. To enhance coverage, as shown in table 10 below, the MTC may be divided into two operation modes (a first mode and a second mode) and four different classes.

The MTC mode of operation may be referred to as CE mode. The first mode and the second mode may be referred to as CE mode a and CE mode B, respectively.

[ Table 10]

The first mode is defined for small coverage supporting full mobility and Channel State Information (CSI) feedback. In the first mode, the number of repetitions is zero or small. Operation in the first mode may have the same operational coverage as UE class 1. The second mode is defined for UEs with very poor coverage conditions, which support CSI feedback and limited mobility. In the second mode, the number of times of repeated transmission is large. The second mode provides up to 15dB coverage enhancement relative to UE class 1 coverage. Each rank of MTC is defined differently during RACH and paging.

Hereinafter, a description will be given of how to determine the MTC operation mode and rank.

The MTC mode of operation is determined by the base station and each class is determined by the MTC UE. Specifically, the base station sends RRC signaling including information for MTC mode of operation to the UE. The RRC signaling may include an RRC connection setup message, an RRC connection reconfiguration message, or an RRC connection re-establishment message. Herein, the term "message" may refer to an Information Element (IE).

The MTC UE determines a rank within an operation mode and transmits the determined rank to a base station. Specifically, the MTC UE determines a rank within an operation mode based on the measured channel quality (e.g., RSRP, RSRQ, SINR, etc.), and notifies the base station of the determined rank using PRACH resources (e.g., frequency, time, preamble, etc.).

MTC guard period

As described above, MTC operates in narrowband. The location of the narrowband may vary in each particular time unit (e.g., subframe or slot). The MTCUs are tuned to different frequencies in each time unit. Therefore, all frequency retuning may require a certain period of time. In other words, a transition from one time unit to the next requires a guard period, and no transmission and reception occurs during the corresponding period.

The guard period varies depending on whether the current link is a downlink or an uplink, and also varies depending on its state. The uplink guard period (i.e., the guard period defined for the uplink) varies depending on the characteristics of the data carried by the first time unit (time unit N) and the second time unit (time unit N + 1). In the case of the downlink guard period, the following condition needs to be satisfied: (1) the first downstream narrowband center frequency is different from the second narrowband center frequency; (2) in TDD, the first uplink narrowband center frequency is different from the second downlink center frequency.

The definition in the conventional LTE will be describedAn MTC guard period. Creation of a group of

A guard period consisting of one SC-FDMA symbol for Tx-Tx frequency retuning between two consecutive subframes. When configuring the high layer parameter ce-retuning symbols,

equal to ce-Returning symbols. If not, then,

is 2. For MTC UEs configured with higher layer parameters srs-UpPtsAdd, a guard period consisting of SC-FDMA symbols is created for Tx-Tx frequency retuning between the first special subframe and the second uplink subframe for frame structure type 2.

Fig. 12 illustrates physical channels available in MTC and a general signal transmission method using the same.

When the MTC UE is powered on or enters a new cell, the MTC UE performs initial cell search in step S1201. Initial cell search involves acquiring synchronization with a base station. Specifically, the mtcu ue synchronizes with a base station by receiving a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) from the base station and obtains information such as a cell Identifier (ID). The PSS/SSS used by the MTC UE for initial cell search may be identical to the PSS/SSS or re-synchronization signal (RSS) of the legacy LTE.

Thereafter, the MTC UE may acquire broadcast information in a cell by receiving a PBCH signal from a base station.

During initial cell search, the MTC UE may monitor the state of a downlink channel by receiving a downlink reference signal (DLRS). The broadcast information transmitted on the PBCH corresponds to the MIB. In MTC, the MIB is repeated in the first slot of subframe #0 and other subframes of a radio frame (subframe #9 in FDD and subframe #5 in TDD).

PBCH repetition is performed such that the same constellation points are repeated on different OFDM symbols to estimate the initial frequency error before PBCH decoding is attempted.

Fig. 13 illustrates an example of system information transmission in MTC.

Specifically, fig. 13(a) illustrates an example of a repetition pattern of subframe #0 in FDD and an example of a frequency error estimation method for a normal CP and a repetition symbol, and fig. 13(b) illustrates an example of transmission of SIB-BR on a wideband LTE channel.

The scheduling information for the new system information block of the bandwidth reduction device (SIB1-BR), including time/frequency location and TBS, is sent in MTC using five reserved bits in the MIB.

The SIB-BR is transmitted directly on the PDSCH without any associated control channel.

The SIB-BR remains unchanged for 512 radio frames (5120ms) to allow a large number of subframes to be combined.

Table 11 shows an example of MIB.

[ Table 11]

In Table 11, the schedulingInfoSIB1-BR field indicates an index of a table defining SystemInformationBlockType1-BR scheduling information. A value of zero indicates that no SystemInformationBlockType1-BR is scheduled. The overall functionality and information carried by the SystemInformationBlockType1-BR (or SIB1-BR) is similar to SIB1 of conventional LTE. The content of SIB1-BR can be classified as follows: (1) a PLMN; (2) a cell selection criterion; and (3) scheduling information for SIB2 and other SIBs.

After the initial cell search is completed, the MTC UE may acquire more detailed system information by receiving MPDCCH and PDSCH based on information in the MPDCCH in step S1202. MPDCCH has the following characteristics: (1) MPDCCH is very similar to EPDCCH; (2) the MPDCCH may be sent once or repeatedly (the number of repetitions is configured by higher layer signaling); (3) supporting multiple MPDCCH and monitoring a set of MPDCCH by a UE; (4) generating an MPDCCH by combining enhanced control channel elements (ecces), and each CCE includes a set of REs; and (5) the MPDCCH supports RA-RNTI, SI-RNTI, P-RNTI, C-RNTI, temporary C-RNTI and semi-persistent scheduling (SPS) C-RNTI.

To complete access to the base station, the MTC UE may perform a random access procedure in steps S1203 to S1206. The basic configuration of the RACH procedure is carried by SIB 2. The SIB2 includes parameters related to paging. The Paging Occasion (PO) is a subframe capable of transmitting the P-RNTI on the MPDCCH. When P-RNTIPDCCH is repeatedly transmitted, PO may refer to a subframe where MPDCCH repetition starts. A Paging Frame (PF) is a radio frame that may contain one or more POs. When DRX is used, the MTC UE monitors one PO per DRX cycle. The Paging Narrowband (PNB) is one on which the MTC UE performs paging message reception.

To this end, the MTC UE may transmit a preamble on the PRACH (S1203) and receive a response message (e.g., a Random Access Response (RAR)) for the preamble on the MPDCCH and the PDSCH related thereto (S1204). The MTC UE may perform a contention resolution procedure including transmitting a PUSCH (physical uplink shared channel) using scheduling information in the RAR (S1205) and receiving an MPDCCH signal and a PDSCH signal related thereto (S1206). In MTC, signals and messages (e.g., Msg1, Msg2, Msg3, and Msg4) transmitted during a RACH procedure may be repeatedly transmitted, and a repetition pattern may be differently configured depending on a Coverage Enhancement (CE) level. Msg1 may represent a PRACH preamble, Msg2 may represent a RAR, Msg3 may represent an uplink transmission at the MTC UE for the RAR, and Msg4 may represent a downlink transmission from the base station for Msg 3. In MTC, signals and messages transmitted during a RACH procedure (e.g., Msg1, Msg2, Msg3, and Msg4) may be repeatedly transmitted, and a repetition pattern may be differently configured depending on a Coverage Enhancement (CE) level. Msg1 may represent a PRACH preamble, Msg2 may represent a RAR, Msg3 may represent an uplink transmission of the RAR at the MTC UE, and Msg4 may represent a downlink transmission of Msg3 from the base station.

For random access, signaling of different PRACH resources and different CE levels is supported. This may provide the same control over the near-far effect of the PRACH by grouping together UEs that experience similar path losses. Up to four different PRACH resources may be signaled to the MTC UE.

The MTC UE measures RSRP using downlink RSs (e.g., CRS, CSI-RS, etc.), and selects one of the random access resources based on the measurement result. Each of the four random access resources has an associated PRACH repetition number and an associated RAR repetition number.

Therefore, MTC UEs in poor coverage need a large number of repetitions in order to be successfully detected by the base station, and need to receive as many RARs as the number of repetitions so that their coverage levels are met.

A search space for RAR and contention resolution messages is defined in the system information and is independent for each coverage level.

The PRACH waveform used in MTC is the same as that in conventional LTE (e.g., OFDM and Zadoff-Chu sequences).

After performing the above-described procedure, the MTC UE may perform reception of MPDCCH signals and/or PDSCH signals (S1207) and transmission of PUSCH signals and/or PUCCH signals (S1208) as a normal uplink/downlink signal transmission procedure. The control information transmitted by the MTC UE to the base station is generally referred to as Uplink Control Information (UCI). The UCI includes HARQ-ACK/NACK, a scheduling request, a Channel Quality Indicator (CQI), a Precoding Matrix Indicator (PMI), a Rank Indicator (RI), and the like.

When the MTC UE has established an RRC connection, the MTC UE blindly decodes MPDCCH in the configured search space to obtain uplink and downlink data allocations.

In MTC, all available OFDM symbols in a subframe are used to transmit DCI. Therefore, time domain multiplexing is not allowed between the control channel and the data channel in the subframe. Thus, as described above, cross-subframe scheduling may be performed between the control channel and the data channel.

MPDCCH schedules PDSCH allocation in subframe # N +2 if MPDCCH is last repeated in subframe # N.

The DCI carried by the MPDCCH provides information about how many times the MPDCCH is repeated so that MTC UEs can know the number of repetitions at the beginning of PDSCH transmission.

The PDSCH allocation may be performed on different narrow bands. Thus, the mtue may need to perform retuning before decoding the PDSCH allocation.

For uplink data transmission, scheduling follows the same timing as for conventional LTE. The last MPDCCH in subframe # N schedules a PUSCH transmission starting in subframe # N + 4.

Fig. 14 illustrates an example of scheduling for each of MTC and legacy LTE.

The legacy LTE allocation is scheduled using the PDCCH, and uses an initial OFDM symbol in each subframe. The PDSCH is scheduled in the same subframe in which the PDCCH is received.

On the other hand, MTC PDSCH is scheduled across subframes, and one subframe is defined between MPDCCH and PDSCH to allow MPDCCH decoding and RF retuning.

The MTC control and data channels may be repeated for a large number of subframes to be decoded under extreme coverage conditions. In particular, the MTC control and data channels may be repeated for up to 256 subframes for MPDCCH and up to 2048 subframes for PDSCH.

4. Narrow-band Internet of things (NB-IoT)

NB-IoTMay refer to a system that provides low complexity and low power consumption based on a system Bandwidth (BW) corresponding to one Physical Resource Block (PRB) of a wireless communication system (e.g., an LTE system, an NR system, etc.).

Herein, NB-IoT may be referred to as another term such as "NB-LTE", "NB-IoT augmentation", "further enhanced NB-IoT", or "NB-NR". The NB-IoT may be replaced with terms defined or to be defined in the 3GPP standard. For convenience of description, all types of NB-IoT are collectively referred to as "NB-IoT".

By supporting MTC devices (or MTC UEs) in a cellular system, IoT may be implemented using NB-IoT. Since one PRB of the system BW is allocated to NB-IoT, frequency can be efficiently used. In addition, considering that in NB-IoT, each UE recognizes a single PRB as one carrier, the PRBs and carriers described herein may be considered to have the same meaning.

Although the present disclosure describes NB-IoT frame structure, physical channels, multi-carrier operation, operation modes, and general signal transmission and reception based on the LTE system, it is apparent that the present disclosure can be applied to next generation systems (e.g., NR systems, etc.). In addition, the details of NB-IoT described in this document may be applied to MTC with similar objectives (e.g., low power, low cost, coverage enhancement, etc.).

Framework and physical resources of NB-IoT

The NB-IoT frame structure may vary depending on the SCS.

Fig. 15 and 16 illustrate examples of SCS-dependent NB-IoT frame structures. Specifically, fig. 15 illustrates a frame structure with SCS of 15kHz, and fig. 16 illustrates a frame structure with SCS of 3.75 kHz. However, the NB-IoT frame structure is not limited thereto, and different SCS (e.g., 30kHz, etc.) may be applied to the NB-IoT by changing the time/frequency unit.

Although the present disclosure describes the NB-IoT frame structure based on the LTE frame structure, this is merely for convenience of description, and the present disclosure is not limited thereto. That is, the method proposed in the present disclosure may be applied to NB-IoT based on a frame structure of a next generation system (e.g., NR system).

Referring to fig. 15, an NB-IoT frame structure for 15kHz SCS may be the same as that of a legacy system (LTE system). In particular, a 10-ms NB-IoT frame may include 10 1-ms NB-IoT subframes, and a 1-ms NB-IoT subframe may include two NB-IoT slots, each slot having a duration of 0.5 ms. Each 0.5-ms NB-IoT slot may include 7 OFDM symbols.

Referring to fig. 16, a 10-ms NB-IoT frame may include five 2-ms NB-IoT subframes, and the 2-ms NB-IoT subframe may include 7 OFDM symbols and one GP. The 2-ms NB-IoT subframes may be referred to as NB-IoT slots or NB-IoT Resource Units (RUs).

Hereinafter, DL and UL physical resources for NB-IoT will be described.

The NB-IoT downlink physical resources may be configured based on physical resources of other communication systems (e.g., LTE system, NR system, etc.) except that the system BW is composed of a specific number of RBs (e.g., one RB 180 kHz). For example, when the NB-IoT downlink supports only 15kHz subcarrier spacing as described above, the NB-IoT downlink physical resource may be configured by limiting the resource grid of the LTE system illustrated in fig. 5 to one RB (i.e., one PRB) in the frequency domain.

NB-IoT uplink physical resources can be configured by limiting the system bandwidth to one RB as in NB-IoT downlink. For example, when the NB-IoT uplink supports 15kHz and 3.75kHz subcarrier spacing as described above, the resource grid of the NB-IoT uplink may be represented as shown in fig. 17. The number of subcarriers may be given in table 12 below

And a time slot period T_slot。

Fig. 17 illustrates an example of a resource grid for NB-IoT uplink.

[ Table 12]

Resource Units (RUs) for NB-IoT uplinks may include SC-FDMA symbols in the time domain and in the frequency domain

A number of consecutive subcarriers. In frame structure type1 (i.e., FDD), it can be given in table 13 below

And

the value of (c). In frame structure type 2 (i.e., TDD), it can be in Table 14[ l 1]]In (1) give

And

the value of (c).

[ Table 13]

[ Table 14]

NB-IoT physical channel

NB-IoT capable base stations and/or UEs may be configured to transmit and receive physical channels and signals that are different from those in legacy systems. Hereinafter, physical channels and/or signals supported in the NB-IoT will be described in detail.

First, NB-IoT downlink will be described. For NB-IoT downlink, an OFDMA scheme with 15kHz subcarrier spacing may be applied. Accordingly, orthogonality between subcarriers may be provided, thereby supporting coexistence with legacy systems (e.g., LTE systems, NR systems, etc.).

In order to distinguish the physical channel of the NB-IoT system from the physical channel of the legacy system, "N (narrowband)" may be added. For example, a DL physical channel may be defined as follows: "Narrowband Physical Broadcast Channel (NPBCH)", "Narrowband Physical Downlink Control Channel (NPDCCH)", "Narrowband Physical Downlink Shared Channel (NPDSCH)", and the like. The DL physical signal may be defined as follows: "Narrowband Primary Synchronization Signal (NPSS)", "Narrowband Secondary Synchronization Signal (NSSS)", "Narrowband Reference Signal (NRS)", "Narrowband Positioning Reference Signal (NPRS)", "narrowband wake-up signal (NWUS)", and the like.

In general, the above-described downlink physical channels and physical signals for NB-loT may be configured to be transmitted based on time-domain multiplexing and/or frequency-domain multiplexing.

NPBCH, NPDCCH, and NPDSCH, which are downlink channels of the NB-IoT system, may be repeatedly transmitted to enhance coverage.

The NB-IoT uses the newly defined DCI format. For example, the DCI format for NB-IoT may be defined as follows: DCI format N0, DCI format N1, DCI format N2, and the like.

Next, NB-IoT uplink will be described. For the NB-IoT uplink, an SC-FDMA scheme with subcarrier spacing of 15kHz or 3.75kHz may be applied. The NB-IoT uplink may support multi-tone (multi-tone) transmission and single-tone (single-tone) transmission. For example, multi-tone transmissions may support subcarrier spacing of 15kHz, while single-tone transmissions may support subcarrier spacing of 15kHz and 3J5 kHz.

For NB-IoT uplink, similar to NB-IoT downlink, an "N (narrowband)" may also be added to distinguish the physical channels of the NB-IoT system from those of the legacy system. For example, the uplink physical channel may be defined as follows: "Narrowband Physical Random Access Channel (NPRACH)", "Narrowband Physical Uplink Shared Channel (NPUSCH)", and the like. The UL physical signal may be defined as follows: "narrow band demodulation reference signal (NDMRS)".

NPUSCH may be configured with NPUSCH format 1 and NPUSCH format 2. For example, NPUSCH format 1 is used for UL-SCH transmission (or transmission), and NPUSCH format 2 may be used for UCI transmission such as HARQ ACK signaling.

NPRACH, which is a downlink channel of the NB-IoT system, may be repeatedly transmitted for enhanced coverage. In this case, frequency hopping may be applied to the repetitive transmission.

Multi-carrier operation in NB-IoT

Hereinafter, a multi-carrier operation in NB-IoT will be described. Multi-carrier operation may refer to the use of multiple carriers of different purposes (i.e., multiple carriers of different types) when a base station and/or UE transmits and receives channels and/or signals in an NB-IoT.

In general, as described above, the NB-IoT may operate in a multi-carrier mode. In this case, the NB-IoT carriers may be divided into anchor carriers (i.e., anchor carriers or anchor PRBs) and non-anchor carriers (i.e., non-anchor carriers or non-anchor PRBs).

From the perspective of the base station, the anchor carrier may represent a carrier for transmitting NPDSCH, which carries NPSS, NSSS, NPBCH, and SIB (N-SIB) for initial access. In other words, in NB-IoT, the carrier used for initial access may be referred to as an anchor carrier, and the remaining carriers may be referred to as non-anchor carriers. In this case, there may be one or more anchor carriers in the system.

NB-IoT modes of operation

The operation mode of NB-IoT will be described. The NB-IoT system may support three modes of operation. Fig. 18 illustrates an example of the operational modes supported in an NB-IoT system. Although the present disclosure describes an NB-IoT operation mode based on an LTE band, this is merely for convenience of description, and the present disclosure is also applicable to other system bands (e.g., NR system bands).

Fig. 18(a) illustrates an in-band system, fig. 18(b) illustrates a guard band system, and fig. 18(c) illustrates an independent system. The in-band system, the guard band system, and the independent system may be referred to as an in-band mode, a guard band mode, and an independent mode, respectively.

An in-band system may represent a system or mode that uses one specific rb (prb) in a legacy LTE band for NB-IoT. To operate an in-band system, some RBs in an LTE system carrier may be allocated.

The guard band system may represent a system or pattern that uses the guard band reserved space in the legacy LTE band for NB-IoT. To operate the guard band system, a guard band of an LTE carrier that is not used as an RB in the LTE system may be allocated. For example, legacy LTE bands may be configured such that each LTE band has a minimum 100kHz guard band at its end. To use 200kHz, two discrete guard bands may be used.

The in-band system and the guard band system may operate in a structure in which NB-IoT co-exists within the legacy LTE band.

Meanwhile, the independent system may represent a system or mode independent of the legacy LTE band. To operate a standalone system, frequency bands (e.g., reallocated GSM carriers) used in a GSM EDGE Radio Access Network (GERAN) may be allocated separately.

The above three operation modes may be independently applied, or two or more operation modes may be combined and applied.

General signaling and reception procedure in 4.5 NB-IoT

Fig. 19 illustrates examples of physical channels available in an NB-IoT and a general signaling method using the physical channels. In a wireless communication system, an NB-IoT UE may receive information from a base station in a Downlink (DL) and transmit information to the base station in an Uplink (UL). In other words, in a wireless communication system, a base station may transmit information to an NB-IoT UE in a downlink and receive information from the NB-IoT UE in an uplink.

The information transmitted and received between the base station and the NB-IoT UE may include various data and control information, and various physical channels may be used depending on the type/usage of the information transmitted and received therebetween. The NB-IoT signal transmission and reception method described with reference to fig. 19 may be performed by a wireless communication device (e.g., the devices of fig. 32 to 37) which will be described later.

When the NB-IoT UE is powered on or enters a new cell, the NB-IoT UE may perform an initial cell search (S1911). Initial cell search involves acquiring synchronization with a base station. In particular, the NB-IoT UE may synchronize with the base station and obtain information such as a cell ID by receiving NPSS and NSSS from the base station. Thereafter, the NB-IoT UE may acquire information broadcast in the cell by receiving the NPBCH from the base station. During initial cell search, an NB-IoT UE may monitor a state of a downlink channel by receiving a downlink reference signal (DL RS).

In other words, when an NB-IoT UE enters a new cell, the base station may perform initial cell search, and more particularly, the base station may synchronize with the UE. Specifically, the base station may synchronize with the NB-IoT UE and send information such as cell ID by sending NPSS and NSSS to the UE. The base station may send the broadcast information in the cell by sending (or broadcasting) the NPBCH to the NB-IoT UEs. The base station may transmit a DL RS to the NB-IoT UE during initial cell search to check a downlink channel status.

After completing the initial cell search, the NB-IoT UE may acquire more detailed system information by receiving NPDCCH and NPDSCH related thereto (S1912). In other words, after the initial cell search, the base station may send more detailed system information by sending NPDCCH and NPDSCH related thereto to the NB-IoT UEs.

Thereafter, the NB-IoT UE may perform a random access procedure to complete access to the base station (S1913 to S1916).

Specifically, the NB-IoT UE may transmit a preamble on NPRACH (S1913). As described above, NPRACH may be repeatedly transmitted based on frequency hopping for coverage enhancement. In other words, the base station may (repeatedly) receive the preamble from the NB-IoT UE through the NPRACH.

Then, the NB-IoT UE may receive a Random Access Response (RAR) for the preamble on NPDCCH and NPDSCH related thereto from the base station (S1914). That is, the base station may send a Random Access Response (RAR) for the preamble on NPDCCH and NPDSCH related thereto to the base station.

The NB-IoT UE may use the scheduling information in the RAR to send NPUSCH (S1915) and perform a contention resolution procedure based on NPDCCH and NPDSCH related thereto (S1916). That is, the base station may receive NPUSCH from the NB-IoT UE based on scheduling information in the RAR and perform a contention resolution procedure.

After performing the above procedure, the NB-IoT UE may perform NPDCCH/NPDSCH reception (S1917) and NPUSCH transmission (S1918) as a normal UL/DL signaling procedure. After the above procedure, the base station may send NPDCCH/NPDSCH to and receive NPUSCH from the NB-IoT UE during the normal uplink/downlink signaling procedure.

In NB-IoT, NPBCH, NPDCCH, NPDSCH, etc. may be repeatedly transmitted for coverage enhancement as described above. In addition, UL-SCH (normal uplink data) and UCI may be transmitted on NPUSCH. In this case, the UL-SCH and UCI may be configured to be transmitted in different NPUSCH formats (e.g., NPUSCH format 1, NPUSCH format 2, etc.).

As described above, UCI means control information transmitted from a UE to a base station. The UCI may include HARQ ACK/NACK, Scheduling Request (SR), CSI, etc. The CSI may include CQI, PMI, RI, and the like. In general, UCI may be sent over NPUSCH in NB-IoT as described above. In particular, the UE may send UCI on the NPUSCH periodically, aperiodically, or semi-persistently according to a request/indication from a network (e.g., a base station).

Initial access procedure in 4.6 NB-IoT

The process of an NB-IoT UE initially accessing a base station is briefly described in the "general signaling and receiving process in NB-IoT" section. In particular, the above process may be subdivided into a process in which the NB-IoT UE searches for an initial cell and a process in which the NB-IoT UE obtains system information.

Fig. 20 illustrates a specific procedure for signaling between a UE and a base station (e.g., NodeB, eNodeB, eNB, gNB, etc.) for initial access in NB-IoT. Hereinafter, a normal initial access procedure in NB-IoT, NPSS/NSSS configuration, and acquisition of system information (e.g., MIB, SIB, etc.) will be described with reference to fig. 20.

Fig. 20 is one example of an initial access procedure in NB-IoT. The name of each physical channel and/or physical signal may be differently set or referred according to a wireless communication system to which NB-IoT is applied. For example, although NB-IoT based on the LTE system is considered in fig. 20, this is only for convenience of description, and the details thereof may be applied to NB-IoT based on the NR system. The details of the initial access procedure may also be applied to MTC.

Referring to fig. 20, an NB-IoT UE may receive a narrowband synchronization signal (e.g., NPSS, NSSS, etc.) from a base station (S2010 and S2020). The narrowband synchronization signal may be transmitted through physical layer signaling.

The NB-IoT UE may receive a Master Information Block (MIB) (e.g., MIB-NB) from a base station on NPBCH (S2030). The MIB may be transmitted through higher layer signaling (e.g., RRC signaling).

The NB-IoT UE may receive a System Information Block (SIB) from the base station on NPDSH (S2040 and S2050). In particular, the NB-IoT UE may receive SIB1-NB, SIB2-NB, etc., on NPDSCH through higher layer signaling (e.g., RRC signaling). For example, SIB1-NB can refer to system information having a high priority among SIBs, while SIB2-NB can refer to system information having a lower priority than SIB 1-NB.

The NB-IoT may receive NRS from the base station (S2060) and may perform an operation through physical layer signaling.

Random access procedure in 4.7 NB-IoT

A procedure in which an NB-IoT UE performs random access to a base station is briefly described in the "general signaling and receiving procedure in NB-IoT" section. Specifically, the above procedure may be subdivided into a procedure in which the NB-IoT UE transmits a preamble to the base station and a procedure in which the NB-IoT receives a response to the preamble.

Fig. 21 illustrates a specific procedure for signaling between a UE and a base station (e.g., NodeB, eNodeB, eNB, gNB, etc.) for random access in NB-IoT. Hereinafter, details of the random access procedure in NB-IoT will be described based on messages for this (e.g., msg1, msg2, msg3, msg 4).

Fig. 21 illustrates an example of a random access procedure in NB-IoT. The name of each physical channel, physical signal, and/or message may vary depending on the wireless communication system to which the NB-IoT is applied. For example, although NB-IoT based on the LTE system is considered in fig. 21, this is only for convenience of description, and the details thereof may be applied to NB-IoT based on the NR system. The details of the initial access procedure may also be applied to MTC.

Referring to fig. 21, an NB-IoT may be configured to support contention-based random access.

First, an NB-IoT UE may select NPRACH resources based on the coverage class of the respective UE. The NB-IoT UE may send a random access preamble (i.e., message 1, msg1) to the base station on the selected NPRACH resource.

The NB-IoT UE may monitor the NPDCCH search space to search for NPDCCHs of DCI scrambled with RA-RNTI (e.g., DCI format N1). Upon receiving the NPDCCH of the DCI scrambled with the RA-RNTI, the UE may receive RAR (i.e., message 2, msg2) from the base station on the NPDSCH related to the NPDCCH. The NB-IoT UE may obtain a temporary identifier (e.g., temporary C-RNTI), a Timing Advance (TA) command, etc., from the RAR. In addition, the RAR may also provide uplink grants for scheduled messages (i.e., message 3, msg 3).

To begin the contention resolution process, the NB-IoT UE may send a scheduled message to the base station. The base station may then send an associated contention resolution message (i.e., message 4, msg4) to the NB-IoT UE to inform the random access procedure of successful completion.

Through the above operations, the base station and the NB-IoT UE may complete random access.

Discontinuous Reception (DRX) procedure in NB-IoT

When the above-described general signal transmission and reception procedure is performed in the NB-IoT, the NB-IoT UE may transition to an IDLE state (e.g., RRC _ IDLE state) and/or an INACTIVE state (e.g., RRC _ INACTIVE state) to reduce power consumption. After transitioning to the idle state and/or the inactive state, the NB-IoT UE may be configured to operate in DRX mode. For example, after transitioning to the idle state and/or the inactive state, the NB-IoT UE may be configured to monitor NPDCCH related to paging only in certain subframes (frames or slots) according to a DRX cycle determined by the base station. Here, the NPDCCH related to paging may refer to an NPDCCH scrambled with a paging access-RNTI (P-RNTI).

Fig. 22 illustrates an example of DRX mode in an idle state and/or an inactive state.

DRX configuration and indication for NB-IoT UEs may be performed as shown in fig. 23. That is, fig. 23 illustrates an example of DRX configuration and indication procedures for an NB-IoT UE. However, the process in fig. 23 is merely exemplary, and the method proposed in the present disclosure is not limited thereto.

Referring to fig. 23, an NB-IoT UE may receive DRX configuration information from a base station (e.g., NodeB, eNodeB, eNB, gNB, etc.) (S2310). In this case, the UE may receive information from the base station through higher layer signaling (e.g., RRC signaling). The DRX configuration information may include configuration information regarding a DRX cycle, a DRX offset, a DRX-related timer, and the like.

Thereafter, the NB-IoT UE may receive a DRX command from the base station (S2320). In this case, the UE may receive the DRX command from the base station through higher layer signaling (e.g., MAC-CE signaling).

Upon receiving the DRX command, the NB-IoT UE may monitor NPDCCH at a specific time unit (e.g., subframe, slot, etc.) based on the DRX cycle (S2330). NPDCCH monitoring may mean the following procedure: a specific part of NPDCCH is decoded based on a DCI format to be received in a corresponding search space and the corresponding CRC is scrambled with a specific predefined RNTI value in order to check whether the scrambled CRC matches an expected value (i.e., is equivalent).

When the NB-IoT UE receives its paging ID and/or information indicating a change in system information through NPDCCH during the process of fig. 23, the NB-IoT UE may initialize (or reconfigure) a connection (e.g., RRC connection) with the base station (e.g., the UE may perform the cell search process of fig. 19). Alternatively, the NB-IoT UE may receive (or obtain) new system information from the base station (e.g., the UE may perform the system information acquisition procedure of fig. 19).

4.9. Cell-specific reference signal (CRS) and Narrowband Reference Signal (NRS)

Fig. 24 is a diagram schematically illustrating a CRS pattern applicable to the present disclosure. In particular, fig. 24 shows a CRS pattern in case of a normal CP. In FIG. 24, R_PIndicating REs for transmitting RSs on antenna port p.

If there is no special configuration, the UE may assume that CRS is transmitted on the following resources in a cell supporting PDSCH transmission.

All DL subframes for frame structure type1

All DL subframes and DwPTS for frame structure type 2

REs used for CRS transmission on any one antenna port in a particular time slot should not be used for any transmission on other antenna ports in the same time slot.

When transmitting CRS in a particular cell, CRS may be frequency shifted, e.g., cell-specific frequency shifted

Then much, the cell-specific frequency shift is determined by the physical layer cell identifier of the cell.

Fig. 25 is a diagram schematically illustrating an NRS pattern applicable to the present disclosure. In FIG. 25[ l2]In, R_PIndicating REs for transmitting RSs on antenna port 2000+ p.

A UE (in particular an NB-IoT UE) according to the present disclosure may assume that NRS is transmitted as follows depending on the following conditions.

(1) Before the UE obtains the higher layer parameter operationcodeinfo:

when using frame structure type1, the UE may assume that NRS is transmitted in subframes #0 and #4 and subframe #9 that does not include NSSS.

When using frame structure type 2, the UE may assume that NRS is transmitted in subframe #9 and subframe #0 that does not include NSSS.

(2) On an NB-IoT carrier on which the UE receives a higher layer parameter operationmode info (i.e., indicating a guard band or standalone higher layer parameter operationmode info) indicating a guard band mode or standalone mode:

when using frame structure type1, the UE may assume that NRS is transmitted in subframes #0, #1, #3, and #4 and subframe #9 not including NSSS until the UE obtains SIB 1-NB.

When using frame structure type1, the UE may assume that NRS is transmitted in subframes #0, #1, #3, and #4, subframe #9 excluding NSSS, and NB-IoT DL subframe after the UE obtains SIB 1-NB.

When using frame structure type 2, the UE may assume that NRS is transmitted in subframe #9, subframe #0, which does not include NSSS, and subframe #4 (if subframe #4 is configured for SIB1-NB transmission) until the UE obtains SIB 1-NB.

When using frame structure type 2, the UE may assume that the NRS is sent in subframe #9, subframe #0 excluding NSSS, subframe #4 (if subframe #4 is configured for SIB1-NB transmission), and NB-IoT DL subframe after the UE obtains SIB 1-NB.

(3) On an NB-IoT carrier on which the UE receives a higher layer parameter operationModeInfo indicating an in-band mode (inband-sameppci) based on the same Physical Cell Id (PCI) or an in-band mode (inband-diffferentpci) based on a different PCI (i.e., a higher layer parameter operationModeInfo indicating an inband-SamePCI or an inband-diffferentpci): for example, in the former case, the NB-IoT and LTE cells share the same physical cell ID and have the same number of NRS ports and the same number of CRS ports. In the latter case, the NB-IoT and LTE cells have different cell IDs.

When using frame structure type1, the UE may assume that the NRS is transmitted in subframes #0 and #4, subframe #9 without NSSS, and subframe #3 with SIB1-NB (if the higher layer parameter addiontransmissionsib 1 is set to TRUE) until the UE acquires SIB 1-NB.

When using frame structure type1, the UE may assume that after the UE obtains SIB1-NB, NRS is transmitted in subframes #0 and #4, subframe #9 without NSSS, subframe #3 with SIB1-NB (if higher layer parameter addiontransmissionsib 1 is set to TRUE), and NB-IoT DL subframe.

When using frame structure type 2, the UE may assume that NRS is transmitted in subframe #9, subframe #0, which does not include NSSS, and subframe #4 (if subframe #4 is configured for SIB1-NB transmission) until the UE acquires SIB 1-NB.

(4) On NB-IoT carriers where there is a higher layer parameter DL-CarrierConfigDedicated-NB and no higher layer parameter inbandCarrierInfo:

when using frame structure type1, the UE may assume that NRSs are transmitted in subframes #0, #1, #3, #4, and #9, and NB-IoT DL subframes, and expect to not transmit NRSs in other DL subframes.

(5) On an NB-IoT carrier where there is a higher layer parameter DL-CarrierConfigDedicated-NB and a higher layer parameter inbandCarrierInfo:

when using frame structure type1, the UE may assume that NRS is transmitted in subframes #0, #4, and #9 and NB-IoT DL subframes, and expect NRS not to be transmitted in other DL subframes.

(6) The UE may assume that no NRS is transmitted to transmit a Narrowband Positioning Reference Signal (NPRS) in a subframe configured by a higher layer parameter, nprsBitmap.

The NRS may be transmitted on either or both of antenna ports 2000 and 2001.

When indicating by higher layers that the UE can assume N^cell _IDIs equal to N^Ncell _IDThe UE may use the following assumptions.

-the number of CRS antenna ports is equal to the number of NRS antenna ports.

CRS antenna ports

0 and 1 correspond to NRS antenna ports 2000 and 2001, respectively.

CRS is available in all subframes where NRS is available.

Indicating that the UE can assume N when failing to pass higher layers^cell _IDIs equal to N^Ncell _IDThe UE may apply the following assumptions.

The number of CRS antenna Ports is obtained from the higher layer parameter eutra-NumCRS-Ports.

CRS is available in all subframes where NRS is available.

The cell specific frequency shift for CRS satisfies the following equation 1.

[ equation 1]

REs used for NRS transmission on any one antenna port in a particular timeslot should not be used for any transmission on other antenna ports in the same timeslot.

NRS is not transmitted in a subframe including NPSS or NSSS.

NRS is not transmitted in the special subframes according to the

special subframe configurations

0 and 5 of the frame structure type 2.

5. Signal transmitting and receiving method between UE and base station applicable to the present disclosure

In a wireless communication system supporting NB-IoT (or MTC), a base station (or network) may manage anchor carriers and non-anchor carriers, which are additionally configurable, that are available for NPSS/NSSS/NPBCH transmission. In systems beyond release 14(Rel-14) NB-IoT, a base station may manage both anchor and non-anchor carriers as carriers for paging.

According to the most recent NB-IoT standard, the UE may monitor the anchor carrier in each DRX cycle that periodically performs Radio Resource Management (RRM) measurements or based on relaxed RRM measurement conditions. The UE may perform RRM measurements to determine whether to perform cell reselection.

However, the radio channel environment on the anchor carrier may be significantly different from the radio channel environment on the non-anchor carrier, and due to such a difference, there may be a limitation on the paging monitoring when the UE performs paging on the non-anchor carrier.

In order to solve the above problems, UE and base station operations related to RRM measurements on non-anchor carriers will be described in detail in this document.

Herein, an anchor carrier and a non-anchor carrier may be defined as follows. Thus, the corresponding configuration can be extended to all configurations interpretable in the same sense.

-anchor carrier: carrier in which UE assumes NPSS/NSSS/NPBCH/SIB-NB transmission in NB-IoT-enabled wireless communication system

-non-anchor carrier: carrier where the UE does not assume NPSS/NSSS/NPBCH/SIB-NB transmission in NB-IoT enabled wireless communication systems

According to recent standard specifications, even if the UE desires paging on non-anchor carriers, the base station may not need to send NRS unless there is a page transmission. Thus, if the UE desires paging on the non-anchor carrier, the UE may not assume whether NRS is sent on the non-anchor carrier until the presence of NPDCCH is confirmed by Blind Decoding (BD). In particular, due to the characteristics of RRM measurements, the presence of the target RS needs to be clearly defined. Therefore, RRM measurements may not be suitable for the non-anchor carrier used for paging (since it is unclear whether to transmit the NRS as the target RS for performing the RRM measurements).

The purpose of a wake-up signal (WUS) that has been introduced recently is to inform the UE whether or not to transmit a paging signal before a Paging Occasion (PO) monitored by the UE. If no paging signal is determined to be transmitted based on the WUS, the UE may operate/switch in/to sleep mode at the location where paging is desired (without detecting the corresponding paging signal).

In a wireless communication system (or network) in which WUS is configured, a UE may perform RRM measurement relaxation (measurement relaxation) based on configuration information. When the UE is configured to perform RRM measurement relaxation, the UE may perform RRM measurements every N DRX cycles instead of performing RRM measurements every DRX cycle.

Accordingly, when a base station transmits NRS on a non-anchor carrier, if a UE is capable of performing WUS operation, power consumption efficiency of the UE may be improved.

In order to solve the above problems, NRS transmission and reception methods (on non-anchor carriers for paging) will be described in detail in this document, taking into account the characteristics of per-UE capabilities.

The NRS transmission and reception method of the present disclosure will be described on the assumption that NRS is transmitted in a valid subframe in which a UE can always expect NRS transmission. In other words, how the base station actually transmits NRSs to the UE will be mainly described in this document. In some implementations, the NRS of the present disclosure may be replaced with other signals (e.g., WUS, additional synchronization signals, or other RSs) with similar purposes.

The proposed methods may be implemented independently, and two or more of the proposed methods may be combined without departing from the spirit of the present disclosure.

The NRS transmitting and receiving method proposed in the present disclosure may be combined with each or at least one of the following processes: initial Access (IA) of the UE, Random Access (RA), and DRX.

(1) Initial Access (IA)

The NRS transmission and reception method proposed in the present disclosure may be performed after the IA procedure of the UE.

In this case, the UE may operate as follows.

The UE establishes a connection with the base station during the IA procedure. During or after the IA procedure, the UE may receive parameters (or control information) predefined or preconfigured to perform the methods proposed in the present disclosure according to one of the following methods.

The UE obtains parameters (or control information) from signaling (e.g., DCI, MAC CE, RS, synchronization signals, etc.) received during the IA procedure.

The UE obtains parameters (or control information) from signaling (e.g., DCI, MAC CE, RS, synchronization signal, RRC signaling, etc.) received in RRC _ CONNECTED state after the IA procedure.

Thereafter, the UE may perform the method proposed in the present disclosure (after the IA procedure) based on the parameters (or control information) received according to the above-described method.

Further, the base station may operate as follows.

The base station may configure the UE with parameters (or control information) for performing the methods proposed in the present disclosure according to one of the following methods.

The base station transmits the parameters (or control information) to the UE through specific signaling (e.g., DCI, MAC CE, RS, synchronization signal, etc.) during the IA procedure.

The base station transmits parameters (or control information) to the UE in the RRC _ CONNECTED state through specific signaling (e.g., DCI, MAC CE, RS, synchronization signal, RRC signaling, etc.) after the IA procedure.

Thereafter, the base station may perform the method proposed in the present disclosure (after the IA procedure) based on the corresponding parameter (or control information).

(2) Random Access (RA)

The NRS transmission and reception method proposed in the present disclosure may be performed after an RA procedure of the UE.

In this case, the UE may operate as follows.

The UE establishes a connection with the base station during the RA procedure. During or after the RA procedure, the UE may receive parameters (or control information) predefined or preconfigured to perform the methods proposed in the present disclosure according to one of the following methods.

The UE obtains parameters (or control information) from signaling (e.g., DCI, MAC CE, RS, synchronization signal, etc.) received during the RA procedure.

The UE obtains parameters (or control information) from signaling (e.g., DCI, MAC CE, RS, synchronization signal, RRC signaling, etc.) received in RRC _ CONNECTED state after the RA procedure.

Thereafter, the UE may perform the method proposed in the present disclosure (after the RA procedure) based on the parameters (or control information) received according to the above-described method.

Further, the base station may operate as follows.

The base station transmits parameters (or control information) to the UE through specific signaling (e.g., DCI, MAC CE, RS, synchronization signal, etc.) during the RA procedure.

The base station transmits parameters (or control information) to the UE in the RRC _ CONNECTED state through specific signaling (e.g., DCI, MAC CE, RS, synchronization signal, RRC signaling, etc.) after the RA procedure.

Thereafter, the base station may perform the method proposed in the present disclosure (after the RA procedure) based on the corresponding parameter (or control information).

(3) Discontinuous Reception (DRX)

With the NRS transmission and reception method proposed in the present disclosure, the UE may receive NPDCCH (or MPDCCH) for the on duration of the above-described DRX cycle and then perform NRS reception after transitioning to the RRC _ CONNECTED state.

In this case, the UE may operate as follows.

The UE may receive parameters (or control information) predefined or preconfigured to perform the methods set forth in the present disclosure according to one of the following methods.

The UE receives parameters (or control information) from the base station through signaling (e.g., DCI, MAC CE, RS, synchronization signal, RRC signaling, etc.) related to DRX operation.

The UE receives the parameters (or control information) through the paging message.

The UE receives parameters (or control information) through RRC signaling in RRC _ CONNECTED state.

Thereafter, the UE may perform the method proposed in the present disclosure in an RRC _ CONNECTED state based on the received parameter (or control information) after receiving the paging message in the DRX mode.

Further, the base station may operate as follows.

The base station transmits parameters (or control information) to the UE through specific signaling (e.g., DCI, MAC CE, RS, synchronization signal, RRC signaling, etc.) during the DRX procedure of the UE.

The base station transmits the parameters (or control information) to the UE through a paging message.

The base station sends the parameters (or control information) to the UE through RRC signaling.

Thereafter, the base station may perform the method proposed in the present disclosure based on the received parameters (or control information) after the UE transmits the paging message while operating in the DRX mode.

The above UE and base station operations related to IA/RA/DRX are merely examples in accordance with the present disclosure. In some implementations, corresponding operations may be performed with respect to all configurations set forth in the present disclosure.

Herein, a valid subframe in which NRS is transmitted may mean a DL subframe in which a UE may expect to transmit a DL signal for NB-IoT.

In the present disclosure, with respect to DL NRS, a UE and a base station may operate as follows.

The base station generates an NRS sequence. Specifically, the base station generates a sequence for NRS according to the following equation 2. In the following equation, N^cell _IDCan use N^Ncell _IDAnd (6) replacing.

[ equation 2]

In equation 2, n_sDenotes the slot number within the radio frame and/denotes the OFDM symbol number within the slot. N is a radical of^max，DL _RBIs determined by the number of subcarriers per RB (N)^RB _sc) Multiple of (d) represents the maximum DL bandwidth configuration. The pseudo-random sequence c (i) in equation 2 may be defined by equation 3.

[ equation 3]

c(n)＝(x₁(n+N_C)+x₂(n+N_C))mod 2

x₁(n+31)＝(x₁(n+3)+x₁(n))mod 2

x₂(n+31)＝(x₂(n+3)+x₂(n+2)+x₂(n+1)+x₂(n))mod 2

Such pseudo-random sequences are defined based on length 31Gold sequences. The length of c (n) is M_PNWherein n ═ 0, 1, · M_PN-1。

In equation 3, N_CIs 1600. Can use x₁(0) 1 and x₁Initializing a first m-sequence with (n) ═ 0, wherein n ═ 1, 2,. and 30, and can be based on

Initializing a second m-sequence, wherein

With values depending on the sequence application.

The pseudo-random sequence generator may be initialized according to equation 4 below.

[ equation 4]

In equation 4, c may be initialized at the start point of each OFDM symbol_init。

The base station maps the sequence generated by the above method to at least one RE and transmits NRS to the UE on the RE. In this case, the at least one RE may be a concept including at least one of a time resource, a frequency resource, or an antenna port.

Fig. 27 is a flowchart schematically illustrating an operating method of a UE applicable to the present disclosure.

The UE receives NRS from the base station. Alternatively, the UE may assume that the NRS is transmitted on a specific RE.

The UE may receive a paging signal transmitted on a non-anchor carrier based on the received NRS. Specifically, the UE may demodulate a paging message transmitted on a PO in DRX based on the received NRS.

It is apparent that operations related to NRS-based paging signal reception on non-anchor carriers (e.g., PDCCH monitoring for the on duration of a DRX cycle, cell reselection including an RA procedure, etc.) are performed together with the above-described DRX operation, RA procedure, etc.

Hereinafter, NRS transmission and reception methods between a UE and a base station will be described in detail based on the above discussion.

5.1 NRS Transmission and reception method 1

The UE may assume that the NRS is transmitted in a duration related to the paging search space regardless of whether a paging signal is actually transmitted on a non-anchor carrier for paging.

In particular, the UE may assume that the NRS is transmitted in the paging search space duration regardless of whether the paging signal is actually transmitted on a non-anchor carrier on which the UE desires transmission of the paging signal.

In this case, the UE may assume that NRS can be transmitted in N valid subframes after PO. The value of N may be determined by a method that will be described in section 6.15.

Alternatively, the UE may assume that the NRS can be transmitted in N valid subframes before the PO. The value of N may be determined by a method that will be described in section 6.15.

NRS transmitting and receiving method 2

When a base station (or network) supports WUS, the UE may assume that NRS can be transmitted during a period in which WUS can be transmitted on a non-anchor carrier for paging.

Specifically, according to the present method, the UE may assume that it is able to transmit NRS during a period in which WUS is transmitted on a non-anchor carrier where paging signal transmission is desired. The base station may be configured to transmit NRS during periods in which WUS is transmitted on a non-anchor carrier where paging signal transmission is desired.

In this case, the period during which WUS is transmitted may be the maximum duration period allowed for WUS transmission.

According to the method, when a WUS-capable UE confirms that there is no paging signal transmission at a transmission location of the WUS, the UE may not wake up to perform NRS-based measurement, thereby improving power efficiency of the UE.

WUS capability

The method can be applied only when the UE has WUS capability. When the UE does not have WUS capability, the UE may (1) assume that NRS is transmitted at an NRS transmission location determined by other methods of the present disclosure, or (2) operate as in the prior art without using enhanced features related to NRS transmission on non-anchor carriers.

When a UE has WUS capability for a base station (or network) in a wireless communication system to which the present method is not applicable, the UE can (1) assume that NRS is transmitted at an NRS transmission position determined by other methods of the present disclosure, or (2) operate as in the prior art without using enhanced features related to NRS transmission on a non-anchor carrier.

Alternatively, when the UE has WUS capability to the base station in the NB-IoT network supporting both the NRS transmission and

reception methods

1 and 2, the UE can assume an NRS transmission position based on only the present method (NRS transmission and reception method 2). Accordingly, the base station can avoid unnecessarily repeating and transmitting the NRS.

Time position

As an example of the method, the UE may assume that NRS can be transmitted at least one subframe among N valid subframes starting from a start subframe starting from a maximum duration of WUS. Thus, the UE may detect WUS and use NRS simultaneously.

As another example of the method, the UE may assume that NRS can be transmitted at least one subframe among N valid subframes before an end subframe where the maximum WUS duration ends. Therefore, the influence of NRS on a WUS transmission period for a UE capable of WUS detection in a short transmission duration can be minimized, and the UE can use NRS after detecting WUS. Thus, UE complexity may be reduced.

As another example of the method, the N value, i.e., the value of the length of the valid subframe in which NRS can be transmitted, may be determined by the method described in section 6.15.

WUS punctured NRS

The method can be applied only when the base station is not transmitting any WUS. When a WUS is transmitted, overlapping REs may be punctured if several REs of the WUS overlap with an NRS. That is, the present method can prevent performance degradation of WUS detection.

In this case, the UE may perform measurement or tracking on the assumption that the WUS or NRS is transmitted. For the case where the UE uses WUS instead of NRS, the base station may provide the UE with information about transmission power of the WUS and/or quasi co-location (QCL) information.

In particular, WUS puncturing by NRS may be applied when a base station or UE does not transmit a specific signal at a specific resource location or does not receive a specific signal. For example, if there is overlap between specific signals (or specific REs), the base station or the UE may puncture a portion of the overlapping signals at a location where the overlap occurs.

NRS transmitting and receiving method 3

When a base station (or network) supports WUS, the UE may assume that NRS can be transmitted in N valid subframes adjacent to a period where WUS transmission can be made on a non-anchor carrier for paging.

Specifically, according to the present method, the UE may assume that NRS is transmitted in at least one subframe among valid subframes adjacent to a period during which WUS is transmitted on a non-anchor carrier where paging signal transmission is desired. The base station may transmit NRS after a period during which the WUS is transmitted on a non-anchor carrier where paging signal transmission is desired.

The present method may have the same advantages as the NRS transmitting and receiving method 2. In addition, the method can also solve both WUS puncturing problem and UE complexity problem caused by NRS transmission.

WUS capability

The WUS capability related operation may be the same as the operation described above in the NRS transmitting and receiving method 2.

Time position

As an example of the method, the UE may assume that NRS can be transmitted at least one subframe among N valid subframes before a start subframe from which the maximum WUS duration starts. Thus, prior to detecting WUS, the UE may determine whether to perform cell reselection by performing RRM measurements on the corresponding carrier (i.e., non-anchor carrier) or to set a warm-up time for channel estimation.

As another example of the method, the UE may assume that NRS can be transmitted at least one subframe among N valid subframes after an end subframe in which the maximum WUS duration ends. Therefore, the UE may perform NRS monitoring by operating the master receiver only when there is a WUS, and this operation may be particularly suitable for low complexity UEs.

As yet another example of the method, there may be or a prescribed (time) gap configured between the WUS transmission period and the period during which NRS transmission is assumed. Accordingly, the UE may be provided with a time for processing NRS and WUS and a preparation time thereof for this purpose.

NRS transmitting and receiving method 4

When a base station (or network) supports WUS, the base station may periodically configure a no DTX WUS (WUS without DTX) for the UE. Here, "no DTX WUS" may mean that WUS is always transmitted.

Specifically, the method proposes that when the UE supports WUS, the base station periodically configures a "no DTX WUS" period for the UE. Here, a no DTX WUS may be interpreted to mean that a WUS is always transmitted regardless of whether a subsequent associated paging signal is transmitted. Conversely, an operation of sending a WUS if there is a subsequent transmission of an associated paging signal as in a WUS defined in release 15NB-IoT, or otherwise not sending a WUS, may be referred to as a "WUS with DTX".

According to the method, the base station can achieve the same object as the NRS by using an RS such as WUS instead of additionally transmitting the NRS on a non-anchor carrier.

Time position

As an example of this approach, a no DTX WUS and a WUS with DTX can share a transmission location. For example, the base station may transmit a no DTX WUS at the location of a WUS with DTX defined in release 15 NB-IoT.

As another example of the method, the transmission period of a DTX-free WUS may be L times the transmission period of a WUS with DTX. In this case, the value of L may be determined according to one of the following options.

(option 1) the value of L may be explicitly configured through higher layer signaling such as SIB or RRC signaling. According to option 1, the base station can implement flexible resource management.

(option 2) the value of L may be determined by the level of RRM measurement relaxation. According to option 2, when RRM measurement relaxation is configured for a WUS-capable UE and when no DTX WUS is used for RRM measurement, unnecessary WUS transmission can be prevented.

Per carrier configuration

As an example of the method, a configuration/application of no DTX WUS may be determined for each carrier. That is, each carrier may have different radio channel environments and different services, and thus whether the method is enabled or disabled for a particular carrier may be determined accordingly.

As another example of the method, DTX free WUS may be configured/applied for/to non-anchor-only carriers. Since synchronization signals such as NPSS/NSSS are transmitted on the anchor carrier and an assumption is made for the anchor carrier that NRS is always transmitted in a valid subframe, DTX-free WUS can be configured/applied for/to non-anchor carriers only to avoid unnecessary signaling overhead increase.

WUS differentiation

When applying the method, a no DTX WUS may include a WUS that can be identified only by a UE that is capable of recognizing a no DTX WUS. For example, a conventional WUS (e.g., a WUS that can be recognized even by a UE that does not have the capability of a DTX WUS) or an additional WUS (e.g., a WUS that can be recognized only by a UE that has the capability of a DTX WUS) may be used during a WUS transmission period in which the DTX-free WUS is applied. In this case, the additional WUS and the legacy WUS may be identified by at least one of sequences and resources distinguished in a time domain and/or a frequency domain.

When using an additional WUS, the UE may recognize that there is no subsequent associated paging signal after detecting the additional WUS. That is, the UE may perform a go-to-sleep (go-to-sleep) operation in which paging monitoring is not performed. In addition, according to the present method, the base station can provide the UE with the RS and, at the same time, avoid unnecessary operations for paging.

WUS duration

When applying the method, DTX-free WUS can be configured to be at least N_minAnd transmitting in one effective subframe. Accordingly, the base station may provide the UE with a minimum transmission length for measurement and tracking. N may be determined by any combination of one or more of the following options_minThe value of (c).

(option 1) can be based on having R_maxDetermining N as a function of inputs_minA value of (1), wherein R_maxIndicating the maximum number of times NPDCCH can be repeated and transmitted in the paging search space. R may be determined by the maximum coverage supported by the base station_max。

(option 2) N may be determined by a function having the size of the maximum WUS duration as an input_minThe value of (c).

(option 3) actual transmission duration over WUS (e.g., 2)^NUnit) to determine N_minThe value of (c).

(option 4) if N is calculated according to a specific criterion_minA value greater than the maximum WUS duration, N may be set_minIs determined to be equal to the maximum WUS duration.

NRS transmitting and receiving method 5.5

A common NRS transmission duration may be configured for a plurality of UEs regardless of the UE _ ID.

Specifically, according to the present method, the UE may assume that the UE commonly guarantees the duration of a valid subframe of periodic NRS transmission on a non-anchor carrier (where paging signal transmission is desired) for each cell (or each carrier). According to the method, the base station can minimize the number of valid subframes required for NRS transmission, thereby reducing signaling overhead.

Any signal that can be applied for a similar purpose (e.g., a signal having a similar purpose and structure as a re-synchronization signal (RSS) introduced in release 15 MTC) can be transmitted applying the determination of the NRS transmission period (i.e., the valid subframe in which the NRS is transmitted) described in the present method.

As an example of the method, the base station may configure the position of the reference subframe where NRS transmission starts and the generation period for the UE through higher layer signaling such as SIB or RRC signaling. For example, the location of the reference subframe may be the first valid subframe on a frame number expressed by a System Frame Number (SFN) or a superframe number (HFN) (or hyper-SFN).

As another example of the present method, all UEs may determine the position of a valid subframe where NRS transmission is expected based on a PO determined by a fixed specific UE _ ID regardless of their UE _ IDs. For example, all UEs may calculate the position of the PO corresponding to UE _ ID ═ X, and then assume the configuration of NRS valid subframes accordingly. In this case, the value of X may be (1) predefined by the standard or (2) indicated by higher layer signaling.

When the method is applied, the N value, i.e., the value of the number (or length) of valid subframes in which NRS can be transmitted, may be determined by the method described in section 6.15.

NRS transmitting and receiving method 6

When the UE is configured with RRM measurement relaxation, the UE may determine/assume a duration of a valid subframe in which NRS is always transmitted based on the level of RRM measurement relaxation.

In particular, when the UE is able to apply RRM measurement relaxation, the method proposed in the present disclosure may be applied as follows.

For example, the following may be determined according to the present method: the period of PO of the valid subframe capable of assuming that NRS transmission is always guaranteed, described in the NRS transmission and reception method 1; the positions and generation periods of WUS of valid subframes capable of assuming that NRS transmission is always guaranteed, described in the NRS transmission and

reception methods

2 and 3; the generation period of the DTX-less WUS described in the NRS transmission and reception method 4; and a generation period of an NRS burst (burst) described in the NRS transmitting and receiving method 5. When the NRS transmitting and receiving method 4 and the NRS transmitting and receiving method 5 are applied, the NRS of the present method can be extended to WUS and burst NRS (or RS).

WUS capability

The method can be applied only when the UE has WUS capability. This is because RRM measurement relaxation may be configured for WUS only capable UEs.

Time period

According to the method, it can be assumed that the period of the NRS valid subframe can be configured to a level equivalent to the RRM measurement relaxation. For example, when RRM measurement relaxation is configured for X DRX cycles, the UE may assume that a valid subframe in which NRS is always transmitted is configured equally for X DRX cycles.

Reference time position

According to the method, the reference point at the start of the period may be determined as the point at which the first NRS valid subframe is expected to occur after SFN-0 or HFN-0. If the point at which the NRS valid subframe can be assumed depends on the UE _ ID, the UE may determine the starting point based on its UE _ ID.

When eDRX is applied, each UE may determine a first PO in a Paging Transmission Window (PTW) after an eDRX cycle as a reference point.

NRS transmitting and receiving method 7

The UE may determine valid subframes in which NRS transmission can be assumed differently depending on whether the UE operates in eDRX mode.

In particular, the present method proposes that the UE configures valid subframes that can assume NRS transmission differently depending on whether the UE operates in eDRX mode or not.

For example, the assumption about NRS transmission valid subframes proposed in the present method may be applied only to UEs that do not use eDRX mode. This is because the UE operating in eDRX mode needs to perform NPSS/NSSS/NPBCH monitoring to acquire time/frequency synchronization and check/obtain system information. That is, in this case, the UE needs to monitor the anchor carrier and thus does not acquire NRS assumption for the non-anchor carrier.

As another example, the assumption about NRS transmission valid subframes may be applied to a UE operating only in eDRX mode.

The NRS transmitting and receiving method 7 may be performed together with the NRS transmitting and receiving methods 2 to 4. For example, when using the NRS transmission and reception method 7, if the NRS (or DTX-free WUS) transmission and reception methods based on the transmission position of WUS described above in the NRS transmission and reception methods 2 to 4 are combined therewith, the UE may be configured to assume NRS transmission valid subframes only at a position of a certain size of the gap. In other words, the UE may assume a valid subframe for NRS transmission that can be assumed only for a certain size of the gap.

For example, when the gaps configured for eDRX are not simultaneous for each UE (that is, when each UE has different gap capabilities), the base station may manage gap 1 and gap 2 (where gap 1> gap 2) to support all UEs. In this case, the position of the gap used by the UE as the NRS transmission position to assume NRS transmission may be fixed to either gap 1 or gap 2. By doing so, the base station can minimize unnecessary NRS transmission.

If the UE recognizes that NRS is not transmitted at a WUS transmission location related to its gap capability, the UE may assume that NRS may be transmitted at a WUS transmission location determined relative to the location of another gap.

Alternatively, the UE may be configured to assume that the NRS is transmitted only at the position of the gap related to its gap capability. In this case, the UE may be configured to not expect NRS at positions of other gaps.

NRS transmitting and receiving method 8

The UE may (i) assume a valid subframe in which NRS is transmitted (including the methods proposed in the present disclosure) based on the duration of DRX (or eDRX) configured in the cell (ii) regardless of whether a paging signal is transmitted on a non-anchor carrier for paging.

In particular, according to the present method, the UE may implicitly recognize an assumption about a valid subframe where NRS transmission is always expected on a non-anchor carrier for paging (i) without any additional configuration (ii) based on the duration of DRX (or eDRX).

For example, the UE may be configured to assume a valid subframe (including the methods proposed in the present disclosure) where NRS transmission is always expected only when the duration of DRX (or eDRX) is less than a predetermined value. When the UE is in sleep mode for a long time, it may be necessary to check the possibility of time/frequency errors occurring due to different UE implementations and the validity of camping on a cell. In this case, the UE may need to check the synchronization signal and the system information on the anchor carrier before performing the NRS-based operation.

NRS transmitting and receiving method 9

The UE may (i) assume a valid subframe in which to transmit NRS (including the methods proposed in this disclosure) based on the pattern of non-anchor carriers used for paging (ii) regardless of whether a paging signal is transmitted or not.

In particular, according to the present method, the UE may implicitly recognize an assumption about a valid subframe where NRS transmission is always expected based on the pattern of non-anchor carriers used for paging.

As an example of the present method, the UE may apply the assumption about NRS transmission on the non-anchor carrier for paging only when the mode of the non-anchor carrier is a specific operation mode. For example, when a non-anchor carrier exists in-band, the UE may be configured not to guarantee signal overhead for the legacy LTE system using assumptions about NRS transmission. However, since there is no limitation on the non-anchor carriers configured for the guard band or the independent system, the UE may be configured to apply the assumption regarding NRS transmission.

As another example of the method, the UE may receive a configuration of NRSs on the non-anchor carrier according to an operation mode of the non-anchor carrier from the base station. For example, the base station may transmit/indicate configuration information about valid subframes in which the UE can always expect NRS transmission to the UE in an operation mode in which carriers managed by the base station exist through higher layer signaling such as SIB or RRC signaling.

As another example of the method, the operation mode of the non-anchor carrier is an in-band same PCI mode, and the UE may assume that a common reference signal or a cell-specific reference signal (CRS) is transmitted in a specific subframe. In this case, when NRS transmission on a non-anchor carrier for paging is assumed in other operation modes, the location of a specific subframe for CRS transmission may be determined in the same manner.

When the non-anchor carrier used for paging is located in-band and operates with the same PCI, the UE may be configured to not assume NRS transmission on a portion of the corresponding carrier where CRS transmission is assumed. According to the present method, since NRS transmission may not be performed if there is no paging signal transmission, the influence on signal transmission for other LTE services can be minimized.

As yet another example of the method, when the operation mode of the non-anchor carrier is an in-band different PCI mode, the UE may assume that the CRS is transmitted in a specific subframe. For this, the UE needs additional information to detect the CRS transmitted on a specific time/frequency resource. The additional information may include information on CRS-to-NRS power offset and information on a location of a corresponding frequency resource in the LTE system bandwidth. The base station may provide the additional information to the UE.

For non-anchor carriers corresponding to different PCI modes in-band, if the number of CRS antenna ports is 4, the UE may desire to send additional NRSs in paging related subframes (as in guard band systems and standalone systems).

The method can be applied to only those UEs that do not know whether NPDCCH or NPDSCH is transmitted in a specific period. In other words, if the UE knows or is able to know whether NPDCCH or NPDSCH is transmitted, the UE may assume that NRS is always transmitted in all (or a portion) of the period in which CRS transmission is assumed, since both NRS and CRS are transmitted.

Fig. 28 is a diagram schematically illustrating an NRS transmission and reception method according to an implementation of the present disclosure. Fig. 28(a) shows a case where it is assumed that both NRS and CRS are transmitted simultaneously, and fig. 28(b) shows a case where it is assumed that only CRS is transmitted.

NRS transmitting and receiving method 10

According to the method, the position of the valid subframe in which the NRS is transmitted may be configured based on a relative gap with respect to the PO.

Specifically, the UE may determine the location of a valid subframe where NRS transmission is always expected based on the relative gap with respect to the PO. According to the method, the UE may measure NRS before monitoring a paging signal and obtain a warm-up time for preparing for a subsequent operation.

In the present method, a gap may be defined as an interval between a start subframe (or an end subframe) of a valid subframe in which NRS is transmitted and PO. In this case, the size of the gap may be (1) predefined by the standard or (2) indicated by higher layer signaling such as SIB or RRC signaling.

As an example of the method, the method may be applied only when there is no WUS configuration for a base station or a UE. When the UE cannot assume an NRS transmission position based on the WUS transmission position, the UE can assume NRS-related operation by maintaining a similar structure thereto, thereby simplifying the operation of the UE.

As another example of the method, the method may be applied when there is a WUS configuration for a base station or UE but the UE does not have WUS capability. When the WUS-related information is not recognized by the WUS-incapable UE, the base station may transmit NRS at the same NRS transmission position as the NRS transmission position of the WUS-capable UE.

In this approach, the definition of PO can be extended to the starting subframe of maximum WUS duration or the ending subframe of maximum WUS duration.

NRS transmitting and receiving method 11

When a base station (or network) supports not only WUS but also UE sub-packets, a period in which NRS (or no DTX WUS) is transmitted can be determined based on the transmission position of WUS. In this case, the UE may assume that NRS is transmitted in at least one subframe among N valid subframes adjacent to a period in which WUS for a specific UE sub-group is transmitted on a non-anchor carrier for paging.

Specifically, when applying UE sub-grouping to WUSs, a UE may assume that NRSs are transmitted in a period of time when WUSs for a specific UE sub-group are transmitted or in a valid subframe adjacent thereto on a non-anchor carrier (where a paging signal is desired). That is, the base station may be configured to transmit NRSs on the non-anchor carrier in a period in which WUSs for a specific UE sub-group are transmitted or in a valid subframe adjacent thereto.

In the present method, UE sub-grouping may refer to dividing UEs desiring to receive a page NPDCCH on the same PO into a plurality of groups. The sub-group WUS may refer to WUS allocated to each UE sub-group on resources distinguished in terms of time, frequency, and/or code domain.

For convenience of description, the method is described in terms of NRS transmission and reception. However, the features of NRS can be similarly applied to other signals such as RS, no DTX WUS, etc.

As an example of the method, a time domain resource may be configured for each subgroup WUS. In this case, the UE may be configured to assume a (valid) subframe in which NRS is transmitted only for WUS using a particular time domain resource (alternatively, the UE may be configured to assume that NRS is transmitted at a location related to one or more time domain WUS resources).

For example, the specific time domain resource may be a time domain resource having an earliest start position among start subframes of the respective sub-group WUSs. In this case, the UE can perform NRS-based measurements before transmitting its WUS, regardless of which UE sub-group the UE belongs to.

As another example, the specific time domain resource may be a time domain resource of a WUS that can be used by UEs that are not UE subgroup capable. In this case, the UE may perform NRS-based measurement even if the UE does not have the UE sub-group capability.

As still another example, the specific time domain resource may be a time domain resource most monitored by the UE among a plurality of UE sub-group WUSs (preferably, sub-group WUSs that should be monitored by all UEs). If the UE does not accurately know the corresponding time domain resource, the base station may provide additional information to the UE to allocate the corresponding resource to the UE.

According to the present method, the following assumptions can be made: the UE can know and use the WUS transmission position of the UE sub-group that is a reference for NRS transmission regardless of the UE sub-group (to which the UE belongs).

When the WUS overhead increases due to the use of UE sub-packets, the present method can prevent the NRS overhead from increasing, which can be increased independently of whether WUS is transmitted.

NRS transmitting and receiving method 12

In the present method, it is assumed that the UE can assume NRS transmission for the duration of the paging search space regardless of whether a paging signal is transmitted on a non-anchor carrier for paging. In addition, it is assumed that the operation mode of the corresponding non-anchor carrier is the in-band same PCI mode. Based on the above assumption, it is proposed that the UE does not assume (or expect) to transmit the CRS in the whole (or a part) of the period in which NRS transmission is assumed.

In particular, when non-anchor carriers for paging operate in-band same PCI mode, the UE may be configured to not assume CRS transmission in a valid subframe in which NRS transmission is always expected.

The method may be suitable when a base station supporting legacy LTE supports CRS muting for the duration of several subframes. For example, a base station may be configured to not transmit CRS in certain subframes to control interference to neighboring base stations.

However, since a UE operating according to the release 15 standard (i.e., an NB-IoT UE) does not receive information from the base station regarding CRS muting, the UE may not apply the assumption regarding CRS muting subframes.

According to the latest standard, a corresponding UE (NB-IoT UE) may desire to always transmit CRS in the subframe in which NRS is transmitted. Therefore, a UE operating according to the latest standard may expect both NRS transmission and CRS transmission (i) when non-anchor carriers for paging are operating in the in-band same PCI mode, and (ii) when NRS is expected to be transmitted in a specific subframe even though a paging signal is not transmitted. According to the above configuration, the base station may be forced to transmit CRS in subframes where CRS muting is applied. The effect expected from applying CRS muting by a base station or other UEs may be reduced if a particular UE becomes able to assume NRS transmission at many locations.

According to the method, the UE may be restricted from assuming CRS transmission in subframes in which NRS transmission is assumed. Thus, the base station connected with the UE may avoid unnecessary and forced CRS transmission.

As an example of the method, the base station may configure a subframe duration in which NRS is always transmitted regardless of whether a paging signal is transmitted on a non-anchor carrier. In this case, if the operation mode is the in-band mode, the base station may determine whether to transmit CRS in all (or a part) of a subframe duration in which NRS is transmitted, depending on the situation (e.g., CRS muting configuration, etc.). The UE may receive information on a subframe duration for which the UE can assume NRS and then assume that NRS is transmitted in a corresponding subframe duration based on the information. However, the UE may not assume CRS transmission based only on configuration information regarding a subframe duration in which NRS transmission is assumed.

As another example of the method, the base station may transmit the CRS in some or all of the NRS transmission locations. For example, the base station may transmit CRS in only (i) subframes where CRS muting is not applied or (ii) subframes where NPDCCH or NPDSCH is actually transmitted among the resources used for NRS transmission.

Preferably, the method can be applied to only those UEs that do not know whether NPDCCH or NPDSCH is actually transmitted in a specific period. In other words, if the UE knows or is able to know whether NPDCCH or NPDSCH is actually transmitted, the UE may assume that CRS is always transmitted in all (or a portion) of the period during which NRS transmission is assumed, since both NRS and CRS are transmitted.

NRS transmitting and receiving method 13

The UE or the base station may use only several POs among all POs as a reference value (or input value) for determining a position of a subframe in which the NRS is transmitted. When NRS is assumed to be sent on all POs, it can act as a burden (burden) for the base station. In this case, the UE or the base station may use the subframe number of the PO and/or the SFN of the PF as a reference value for selecting several POs.

The method proposes that when determining a subframe in which NRS is transmitted based on a PO, a UE or a base station selects a PO including the subframe in which NRS is transmitted. In the present method, the position of a subframe in which the UE can assume NRS transmission (regardless of paging signal transmission) may be determined as a relative position with respect to the PO. In this case, the POs may be all or several POs managed by the base station.

For example, to determine several POs, the UE may use a PO satisfying the following equation 5 in determining the position of a subframe in which NRS transmission is assumed.

[ equation 5]

S mod R＝(Q+1)mod 2

In equation 5, S denotes an SFN of the PF in which the PO is located, and Q denotes a subframe number (i.e., an index of the subframe in one frame in which the PO is located).

When a PO satisfies the above equation 5, the base station may transmit NRS in a subframe corresponding to the PO according to a predetermined rule even if a paging signal is not transmitted on the corresponding PO. The UE may assume that the NRS is transmitted in a subframe corresponding to the PO.

When the PO does not satisfy equation 5 above, the base station may not transmit the NRS if the base station does not transmit the paging signal on the corresponding PO. The UE may be configured to not assume NRS transmission based on POs that does not satisfy equation 5 and does not have paging signal transmission.

Determination of R

In equation 5, R is a value for determining a generation period of a subframe including NRS. The value of R may be predefined by a standard.

For example, the value of R may be fixed to 2. T refers to the DRS cycle of the UE, and nB is a parameter used to calculate the nB-IoT paging carrier and may have one of the following values: 4T, 2T, T, T/2, T/4, T/8, T/16, T/32, T/64, T/128, T/256, T/512 and T/1024. The value of nB may be configured by the PCCH-Config-nB-r13 in the higher layer parameter RadioResourceConfigCommonSIB-nB. When nB > T/2, the number of subframes in which NRS is transmitted may not be set to a large value because there is a PO every three frames.

As another example, the value R may be fixed to 1. When nB > T/2, the number of subframes in which NRS is transmitted may be constant for each PO.

When the value of R is predetermined as described above, the base station may not transmit any signaling for determining the NRS transmission pattern to the UE.

Unlike the above example, R of equation 5 may be semi-statically configured by the base station through higher layer signaling such as SIB or RRC signaling. In this case, the value of R may determine a generation period of the NRS transmission pattern. In other words, the value of R may determine the density of subframes in which the base station needs to always transmit NRS regardless of whether a paging signal is transmitted.

If the base station can transmit NRS at a higher density, the base station can increase the NRS density by decreasing the value of R. On the other hand, the base station may reduce the NRS density by increasing the value of R, i.e., by increasing the occurrence/generation period of the subframe in which the base station transmits (or needs to transmit) NRS regardless of paging signal transmission. That is, as the value of R increases, the number of POs satisfying the equation S mod R ═ (Q +1) mod2 decreases.

In equation 5, the value of R may be determined by the paging parameter nB used to determine PO.

The paging parameter nB represents the number of POs present within one paging cycle for all UEs in the cell. Thus, the paging parameter nB may be used to determine the interval between different POs.

If nB is greater than T, the frames on all SFN can include two or more POs. Based on this, R can be set to 2 in the case of nB ≧ 2T, and R can be set to 1 in the case of nB < 2T.

If two or more POs exist in one frame, the base station can adjust the number of NRS transmission subframes based on the value of R by reducing the frequency of occurrence of POs in which NRS is transmitted. In the opposite case (i.e., when there is one PO or no PO in one frame), the base station may configure an NRS subframe over all POs based on the value of R so that a UE monitoring each PO can equally use NRS.

Supplementary example (modification to equation 5)

In equation 5, when the value of R is greater than or equal to 2, the PO monitored by the UEs having certain UE _ IDs may not include NRS subframes (directly) related thereto.

In this case, since the UE does not have an NRS subframe related to a PO that the UE should monitor, the UE may use the position of a subframe related to a neighboring PO (not a PO that the UE should monitor). According to this configuration, there may be a difference between gains obtained by the UE due to a time difference between the NRS subframe and the actual PO.

In view of the above, equation 5 may be modified to equation 6. According to equation 6, a method of determining the position of the NRS transmission subframe may be periodically changed.

[ equation 6]

S mod R＝(Q+α)mod 2

In equation 6, the value of α may be determined by SFN. For example, the value of α may be determined to be 0 or 1 for a period of T frames.

Since the above problem of equation 5 occurs only when nB is greater than or equal to T, the value of α may be determined according to equation 7 depending on the value of nB.

[ equation 7]

Determining NRS subframe duration

Based on the position of the PO satisfying the conditions in the above equation, the UE may determine the position of the subframe in which NRS transmission is assumed as follows. The UE may assume that the NRS is transmitted in the first N1 subframes (such frame is referred to as a first subframe) among 10 valid subframes (or NB-IoT DL subframes) before the PO and N2 consecutive valid subframes (or NB-IoT DL subframes) after the PO (such frame is referred to as a second subframe). The base station may be configured to transmit NRSs in the first N1 subframes (i.e., N1 first subframes) among 10 valid subframes (or NB-IoT DL subframes) before PO and N2 consecutive valid subframes (or NB-IoT DL subframes) after PO (i.e., N2 second subframes). The values of N1 and N2 may be determined based on the value of nB and/or the number of valid subframes (i.e., nB-IoT DL subframes) in one frame.

Fig. 29 is a diagram schematically illustrating an NRS transmission and reception method according to an implementation of the present disclosure. Specifically, fig. 29 shows the position of a subframe in which an NRS is transmitted based on a PO satisfying R2, N1 8, and equation 5 (regardless of whether a paging signal is actually transmitted). In fig. 29, horizontal hatching (or hatching in the middle row of each nB value) indicates the position of a PO managed by a base station, and diagonal hatching (or hatching in the bottom row of each nB value) indicates the position of a subframe where NRS transmission can be assumed.

NRS transmitting and receiving method 14

According to the method, only a PO having a specific frame number (e.g., SF #9) may be used to determine the position of a subframe in which NRS (or assumed NRS transmission) is transmitted, and a PO having other subframe numbers may not be used to determine the position of a subframe in which NRS (or assumed NRS transmission) is transmitted. In this case, the position and duration of the subframe in which NRS is transmitted may be determined by the value of nB.

Specifically, according to the present method, a PO including a subframe in which NRS (or assumed NRS transmission) is transmitted may be used as a reference value for determining a subframe in which NRS is transmitted. In this case, the location of the subframe in which NRS transmission is assumed (regardless of whether paging is transmitted) may be determined as a relative location with respect to the PO. The POs may be some or all POs managed by the base station.

The UE may use all POs located at subframe #9 to determine the location of the subframe in which NRS transmission is assumed.

For example, when nB ≦ T/2, since there is one PO for every two frames, there may be a frame including a PO and a frame not including a PO from the perspective of the base station. In this case, the position of the subframe in which NRS (or assumed NRS transmission) is transmitted may be determined based on subframe #9 of the frame including PO.

As another example, when nB ═ T, a PO may be included in each frame from the perspective of the base station. Thus, a PO may be located at subframe #9 in each frame, and the position of a subframe in which NRS (or assumed NRS transmission) is transmitted may be determined based on each PO.

As another example, when nB > T, each frame may include one or more POs from the perspective of the base station. In this case, the position of the subframe in which NRS (or assumed NRS transmission) is transmitted may be determined based on a PO corresponding to subframe #9 among one or more POs included in the frame.

According to the method, the length of one NRS subframe corresponding to each PO can be determined by the value of nB. For example, NRSs may be transmitted in the first N1 subframes (such frame is referred to as a first subframe) among 10 valid subframes (or NB-IoT DL subframes) before PO and N2 consecutive valid subframes (or NB-IoT DL subframes) after PO (such frame is referred to as a second subframe). In other words, the UE may assume that the NRS is transmitted in the first subframe and the second subframe. The values of N1 and N2 may be determined based on the value of nB and/or the number of valid subframes (i.e., nB-IoT DL subframes) in one frame.

According to the present method, the UE can always expect NRS transmission at a fixed location without solving a complex formula and judging conditions. In addition, the base station may adjust the number of subframes required for NRS transmission to be suitable for the density of POs.

5.15. Method of determining number of valid subframes (for NRS transmission) according to the present disclosure

The number N of valid subframes in which NRS (or assumed NRS transmission) is sent may be determined by one of the following methods: a first method to an eighth method or any combination of two or more of these methods for determining the number of valid subframes.

In this section, a method of determining the number of valid subframes in which a UE can always expect NRS transmission will be described in detail. For example, a method of determining the number of valid subframes in which a UE can always expect NRS transmission may be performed together with the above-described NRS transmission and reception method.

According to the methods presented in this section, a minimum duration of valid subframes for which the UE can expect NRS transmission may be provided.

Although it is described in this section how to determine the number of valid subframes for NRS, this configuration can be equally applied to WUS or other RSs.

According to the methods described in this section, the UE can assume that at least N valid subframes are always available for NRS transmission regardless of whether a paging signal or WUS is transmitted. Thus, the base station can ensure that the UE performs measurement or tracking based on NRS.

5.15.1 first method for determining the number of valid subframes

The number N of valid subframes in which NRS is sent (or an NRS transmission is assumed) may be predetermined by the specification.

In this case, no signaling overhead is generated between the base station and the UE.

For example, when the UE assumes N valid subframes before PO as NRS subframes based on the NRS transmission and reception method 1, the UE may determine the value of N according to a first method for determining the number of valid subframes.

5.15.2. Second method for determining number of valid subframes

May be configured by having R configured for a search space for paging_maxThe number N of active sub-frames in which NRS is sent (or NRS transmission is assumed) is determined as a function of the input.

According to the method, the base station may adjust the number of valid subframes in which NRS (or assumed NRS transmission) is transmitted, thereby controlling/reducing signaling overhead. In addition, the carrier wave modulation method is based on the R which changes for each carrier wave_maxTo determine the number of valid subframes for each carrier, the UE and the base station can determine the number of NRS-related valid subframes without additional signaling.

As an example of the present method, the number N of valid subframes included in NRS transmission may be configured to satisfy the following equation 8.

[ equation 8]

N＝Rmax*α

In this case, it is possibleThe value of N is configured to always satisfy the following condition: n is greater than or equal to the minimum size N_SAnd/or less than or equal to the maximum size N_L. In equation 8, α is a scaling factor, where α may be indicated (1) with a fixed value determined by the specification or (2) by higher layer signaling such as SIB or RRC signaling.

As another example of the method, the number N and R of valid subframes included in NRS transmission may be specified in a specific table_maxThe relationship between them. Thus, the UE and base station may be able to correlate R based on a particular table_maxThe value of N is chosen.

5.15.3. Third method for determining number of valid subframes

The number N of valid subframes in which NRS is transmitted (or NRS transmission is assumed) may be indicated by higher layer signaling (e.g., SIB or RRC signaling) received from the base station.

According to the method, the base station can flexibly manage the number of valid subframes for NRS transmission depending on network situations.

In the method, the number of active subframes, N, may be configured (independently) for each cell, thereby reducing the base station signaling overhead related to the number of active subframes.

In the method, the number N of valid subframes may be configured for each carrier. Accordingly, the base station may configure the number of valid subframes for NRS in consideration of differences in radio channel environments, such as applicability of power boosting for each carrier.

5.15.4. Fourth method for determining the number of valid subframes

The number N of valid subframes in which NRS is transmitted (or NRS transmission is assumed) may be determined by a function having the size of the maximum WUS duration as an input.

According to the method, the base station may adjust (e.g., reduce) the number of valid subframes used for NRS transmission, thereby reducing signaling overhead. Further, the UE and base station may be based on R configured differently for each carrier_maxIs used to (implicitly) determine the significand for the NRSThe number of frames, and thus no additional signaling is required.

As an example of the present method, the number N of valid subframes included in NRS transmission may be configured to satisfy the following equation 9.

[ equation 9]

N＝R_{WUS_max}*α

In equation 9, R_{WUS_max}Indicating the maximum duration of the WUS.

When the number N of NRS-related valid subframes is determined by equation 9, the value of N may be configured to always satisfy the following condition: n is greater than or equal to the minimum size N_SAnd/or less than or equal to the maximum size N_L. In equation 9, α is a scaling factor, where α may be indicated (1) with a fixed value determined by the specification or (2) by higher layer signaling such as SIB or RRC signaling.

As another example of the method, the number N and R of valid subframes included in NRS transmission may be specified in a specific table_{WUS_max}The relationship between them. Thus, the UE and base station may be able to correlate R based on a particular table_{WUS_max}The value of N is chosen.

5.15.5. Fifth method for determining number of valid subframes

The number N of valid subframes in which NRS (or assumed NRS transmission) is sent may be determined for each paging search space candidate.

Specifically, when NRS transmission is guaranteed in N valid subframes within the duration of the paging search space, the value of N and the duration of the valid subframes may be determined by the same rule as the rule for configuring the paging search space candidates. In this case, the UE may be configured to use NRS based on the candidate value of N. Accordingly, a minimum criterion for the UE to use NRS may be provided, thereby reducing UE complexity. Further, the base station may flexibly adjust the number of valid subframes for NRS transmission depending on network situations.

5.15.6. A sixth method for determining the number of valid subframes

The number N of valid subframes in which NRS (or assumed NRS transmission) is transmitted may be determined by the actual transmission duration of the WUS.

Specifically, when NRS transmission is guaranteed in N valid subframes within the maximum WUS duration, the value of N and the duration of the valid subframes may be determined by the same rule as that for the actual transmission duration. In this case, the UE may be configured to use NRS based on the candidate value of N. Accordingly, a minimum criterion for the UE to use NRS may be provided, thereby reducing UE complexity. Further, the base station may flexibly adjust the number of valid subframes for NRS transmission depending on network situations.

5.15.7. Seventh method for determining number of valid subframes

The number N of valid subframes in which NRS is transmitted (or NRS transmission is assumed) may be limited to be greater than or equal to (or less than or equal to) a specific value.

According to the method, a lower limit may be set for N. Accordingly, the base station may guarantee a minimum NRS transmission (i.e., an NRS transmission having a minimum duration) for the UE to perform an NRS-based operation. For example, assume that the lower limit of N is N_minAnd the value of N calculated/configured by a specific method is N', the base station may determine the number of valid subframes N for NRS transmission according to the following equation: n ═ max (N)_min,N’)。

According to the present method, an upper limit may be set for N. Accordingly, the base station can prevent an overhead increase caused by unnecessary NRS transmission. For example, assume that the upper limit of N is N_maxAnd the value of N calculated/configured by a specific method is N', the base station may determine the number of valid subframes N for NRS transmission according to the following equation: n is min (N)_max,N’)。

According to the method, an upper limit (N) may be set for N_max) And lower limit (N)_min) And both. In this case, the base station may determine the number N of valid subframes for NRS transmission according to the following equation: n ═ max (N)_min,min(N_maxN '), where N' represents the number of valid subframes determined by the various methods described above.

5.15.8. Eighth method for determining the number of valid subframes

The number N of valid subframes in which NRS is sent (or an NRS transmission is assumed) may be determined by the mode of operation.

According to the present method, when there is additional available information (or signaling) in several operating modes, the base station and the UE may configure/assume a relatively short NRS transmission duration in view of the additional available information. According to the present method, the base station and the UE may configure/assume the number of valid subframes for NRS transmission in consideration of subframes for other signal transmissions than NB-IoT transmission in several operation modes.

For example, assume an in-band mode in which the number of valid subframes for NRS transmission is assumed to be N1, and other operating modes (e.g., guard band mode, standalone mode, etc.) in which the number of valid subframes for NRS transmission is assumed to be N2. In this case, N1 and N2 may be configured to satisfy the following condition: n1< N2. By controlling the number of subframes in which NRS transmission is assumed in the in-band mode as described above, it is possible to minimize the restriction on the scheduling of signals/channels that LTE UEs should receive and the performance degradation caused thereby.

As another example, assuming that in the in-band same PCI mode, in which the number of valid subframes of NRS transmission is assumed to be N1, and in other operation modes (e.g., in-band different PCI mode, guard band mode, independent mode, etc.), in which the number of valid subframes of NRS transmission is assumed to be N2, N1 and N2 may be configured to satisfy the following conditions: n1< N2. Accordingly, the UE may obtain additional information based on CRS assumptions provided in the in-band same PCI mode, and in this case, the NRS transmission duration may be set to be relatively short compared to other operation modes.

As still another example, the number N of valid subframes in which NRS transmission is assumed may be fixed to a specific value depending on an operation mode by a standard. Thus, the UE and the base station may obtain the relevant information without additional signaling overhead.

As another example, the number N of valid subframes in which NRS transmission is assumed may be configured to have a prescribed ratio or offset for each operation mode. The specified ratio or offset may be fixed by a standard. Therefore, even in a case where it is assumed that the number of valid subframes of NRS transmission is explicitly/implicitly determined by other parameters rather than fixed, the UE and the base station can obtain related information without additional signaling on the number of valid subframes for each operation mode.

The UE checks whether there is a specific PO satisfying a specific condition among a plurality of POs related to the UE (S3001).

In order to determine a specific PO, the above-described NRS transmission and reception method 13 or 14 may be used.

Referring to equation 5 of the NRS transmission and reception method 13, S mod R ═ Q +1) mod 2. This can be interpreted to mean that the remainder of dividing the SFN of the PF where the PO is located by R is equal to the remainder obtained by dividing a value obtained by adding 1 to the subframe number including the PO by 2. A PO satisfying the above conditions may be regarded as a specific PO.

Regarding the entry of (Q +1) mod2, since SFN has a value of 0 to 9, Q +1 may be a value of 1 to 10. When the result of (Q +1) mod2 is 1, the value of Q may be an even number such as 0, 2, 4, 6, or 8, since the remainder of dividing (Q +1) by 2 should be 1. In contrast, when the result of (Q +1) is 0, the value of Q may be an odd number such as 1, 3, 5, 7, or 9, because the remainder of dividing (Q +1) by 2 should be 0. Thus, a specific PO is determined depending on whether the subframe number in which the PO is located is even or odd.

With respect to the terms of S mod R, if the value of R is fixed to 2, then the result of S mod R should be either 0 or 1. Thus, whether the condition is satisfied may be determined depending on whether S is even or odd. In S mod R ═ (Q +1) mod2, if R is 2, 1 is added to Q. Therefore, when S is even, Q should be odd. Conversely, when S is odd, Q should be even. That is, when the SFN of the PO is even/odd and the subframe number in which the PO is located is odd/even opposite to the SFN, the PO may be a specific PO.

With respect to the entries of S mod R, if the value of R is fixed to 1, the result of S mod R is always fixed to 0. To satisfy the following equation: (Q +1) mod2 is 0, Q should be an odd number regardless of the value of S. That is, when the subframe number in which the PO is located is not related to the SFN of the PO, the PO may be a specific PO.

Referring to equation 6 of the NRS transmission and reception method 13, S mod R ═ Q + a) mod 2. This can be interpreted to mean that the remainder of dividing the SFN of the PF where the PO is located by R is equal to the remainder obtained by dividing a value obtained by adding a to the subframe number where the PO is included by 2. A PO satisfying the above conditions may be regarded as a specific PO.

According to the NRS transmitting and receiving method 14, when the number of subframes in which a PO is located is a specific number, the PO may be a specific PO. For example, a PO may be a specific PO only when the subframe number in which the PO is located is 9.

When it is determined that the specific PO satisfies the specific condition, the UE determines a time period for receiving the NRS based on the specific PO (S3002).

Thereafter, the UE receives NRS in the determined period of time (S3003). Although NRS is taken as an example, the UE may receive the CRS together with the NRS or only the CRS without the NRS.

The UE determines a specific PO from among the POs according to a predetermined rule (S3102).

The base station generates an NRS (S3101) and then transmits the NRS to the UE in a time period determined based on a specific PO according to a predetermined rule (S3103).

The UE receives NRS from the base station in a time period determined based on the specific PO (S3104).

Although NRS is taken as an example, the UE may receive the CRS together with the NRS or only the CRS without the NRS.

As each of the examples of the proposed method can be included as one method for implementing the present disclosure, it is apparent that each example can be considered as the proposed method. Although the proposed methods can be implemented independently, some of the proposed methods can be combined (or merged) to arrive at an implementation. Furthermore, it may be specified that information on whether the proposed method is applied (or information on rules related to the proposed method) should be transmitted from the base station to the UE through a predefined signal (e.g., a physical layer signal, a higher layer signal, etc.).

7. Examples of communication systems to which the disclosure is applied

The various descriptions, functions, processes, proposals, methods and/or operational flow diagrams of the present disclosure described in this document may be applied to, but are not limited to, various fields requiring wireless communication/connection (e.g., 5G communication) between devices.

Hereinafter, a description will be given in detail with reference to the accompanying drawings. In the following drawings/description, the same reference numerals may denote the same or corresponding hardware, software, or functional blocks, unless otherwise specified.

Fig. 32 illustrates a communication system 1 applicable to the present disclosure.

Referring to fig. 32, a communication system 1 applicable to the present disclosure includes a wireless device, a base station, and a network. Herein, a wireless device denotes a device that performs communication based on a radio access technology (e.g., 5G NR, LTE, etc.) and may be referred to as a communication/radio/5G device. The wireless devices may include, but are not limited to, a robot 100a, vehicles 100b-1 and 100b-2, an augmented reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an Internet of things (IoT) device 100f, and an Artificial Intelligence (AI) device/server 400. for example, a vehicle may include a vehicle with wireless communication capabilities, an autonomous vehicle, and a vehicle capable of performing communication between vehicles Home appliance devices, digital signage, vehicles, robots, and the like. Handheld devices may include smart phones, smart tablets, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., laptops). The home appliances may include a TV, a refrigerator, and a washing machine. The IoT devices may include sensors and smart meters. For example, the network and base stations may be implemented as wireless devices, and a particular wireless device 200a may operate as a base station/network node for other wireless devices.

The wireless devices 100a to 100f may connect to the network 300 via the base station 200. AI technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may connect to the AI server 400 via the network 300. The network 300 may include a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although the wireless devices 100a to 100f may communicate with each other through the base station 200/network 300, the wireless devices 100a to 100f may perform direct communication (e.g., sidelink communication) with each other without assistance from the base station 200/network 300. For example, vehicles 100b-1 and 100b-2 may perform direct communication (e.g., V2V/V2X communication). IoT devices (e.g., sensors) may perform direct communication with other IoT devices (e.g., sensors) or with other wireless devices 100 a-100 f.

A wireless communication/

connection

150a, 150b, or 150c may be established between a wireless device 100 a-100 f and a base station 200 or between one base station 200 and another base station 200. Herein, wireless communications/connections may be established over various RATs (e.g., 5G NRs), such as UL/DL communications 150a, sidelink communications 150b (or D2D communications), or inter-base station communications (e.g., relays, Integrated Access Backhaul (IAB), etc.). The wireless device and the base station may transmit/receive radio signals to/from each other through the wireless communication/connection 150a to 150 c. For example, signals may be transmitted/received through various physical channels for wireless communication/connection 150a to 150 c. To this end, at least a portion of various configuration information configuration procedures, signal processing procedures (e.g., channel coding/decoding, modulation/demodulation, resource mapping/demapping, etc.), and resource allocation procedures for radio signal transmission/reception may be performed based on various proposals of the present disclosure.

8. Examples of wireless devices to which the disclosure applies

Fig. 33 illustrates a wireless device applicable to the present disclosure.

Referring to fig. 33, the first wireless device 100 and the second wireless device 200 may transmit radio signals through various RATs (e.g., LTE and NR). Herein, { first wireless device 100 and second wireless device 200} may correspond to { wireless device 100x and base station 200} and/or { wireless device 100x and wireless device 100x } of fig. 33.

The first wireless device 100 may include one or more processors 102 and one or more memories 104 and additionally one or more transceivers 106 and/or one or more antennas 108. The processor 102 may control the memory 104 and/or the transceiver 106 and may be configured to implement the descriptions, functions, procedures, proposals, methods and/or operational flow diagrams disclosed in this document. For example, the processor 102 may process information within the memory 104 to generate a first information/signal and then transmit a radio signal including the first information/signal through the transceiver 106. The processor 102 may receive the radio signal including the second information/signal through the transceiver 106 and then store information obtained by processing the second information/signal in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for performing a portion or all of a process controlled by the processor 102 or for performing the descriptions, functions, procedures, proposals, methods and/or operational flow diagrams disclosed in this document. Herein, the processor 102 and memory 104 may be part of a communication modem/circuit/chip designed to implement a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and transmit and/or receive radio signals through one or more antennas 108. Each of the transceivers 106 may include a transmitter and/or a receiver. The transceiver 106 may be used interchangeably with a Radio Frequency (RF) unit. In this disclosure, a wireless device may represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202 and one or more memories 204 and additionally one or more transceivers 206 and/or one or more antennas 208. The processor 202 may control the memory 204 and/or the transceiver 206 and may be configured to implement the descriptions, functions, procedures, proposals, methods and/or operational flow diagrams disclosed in this document. For example, the processor 202 may process information within the memory 204 to generate a third information/signal and then transmit a radio signal including the third information/signal through the transceiver 206. The processor 202 may receive a radio signal including the fourth information/signal through the transceiver 106 and then store information obtained by processing the fourth information/signal in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code including instructions for performing a portion or all of a process controlled by the processor 202 or for performing the descriptions, functions, procedures, proposals, methods and/or operational flow diagrams disclosed in this document. Herein, the processor 202 and memory 204 may be part of a communication modem/circuit/chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and transmit and/or receive radio signals through one or more antennas 208. Each of the transceivers 206 may include a transmitter and/or a receiver. The transceiver 206 may be used interchangeably with the RF unit. In this disclosure, a wireless device may represent a communication modem/circuit/chip.

Hereinafter, hardware elements of the

wireless devices

100 and 200 will be described in more detail. One or more protocol layers may be implemented by, but are not limited to, one or more processors 102 and 202. For example, the one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). The one or more processors 102 and 202 can generate one or more Protocol Data Units (PDUs) and/or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods and/or operational flow diagrams disclosed in this document. The one or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flow diagrams disclosed in this document. The one or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flow diagrams disclosed in this document and provide the generated signals to one or

more transceivers

106 and 206. The one or more processors 102 and 202 can receive signals (e.g., baseband signals) from the one or

more transceivers

106 and 206 and retrieve PDUs, SDUs, messages, control information, data, or information in accordance with the descriptions, functions, procedures, proposals, methods, and/or operational flow diagrams disclosed in this document.

The one or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. By way of example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in the one or more processors 102 and 202. The descriptions, functions, procedures, proposals, methods and/or operational flow diagrams disclosed in this document may be implemented using firmware or software, and the firmware or software may be configured to include modules, procedures or functions. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods and/or operational flow diagrams disclosed in this document may be included in the one or more processors 102 and 202 or stored in the one or

more memories

104 and 204 to be driven by the one or more processors 102 and 202. The descriptions, functions, procedures, proposals, methods and/or operational flow diagrams disclosed in this document may be implemented using firmware or software in the form of codes, commands and/or command sets.

The one or

more memories

104 and 204 may be connected to the one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, instructions, and/or commands. The one or

more memories

104 and 204 may be configured from read-only memory (ROM), Random Access Memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard drives, registers, cache memory, computer-readable storage media, and/or combinations thereof. The one or

more memories

104 and 204 may be internal and/or external to the one or more processors 102 and 202. The one or

more memories

104 and 204 may be connected to the one or more processors 102 and 202 through various techniques, such as wired or wireless connections.

The one or

more transceivers

106 and 206 may transmit user data, control information, and/or radio signals/channels referred to in the method and/or operational flow diagrams of this document to one or more other devices. The one or

more transceivers

106 and 206 may receive user data, control information, and/or radio signals/channels referred to in the descriptions, functions, procedures, proposals, methods and/or operational flow diagrams disclosed in this document from one or more other devices. For example, the one or

more transceivers

106 and 206 may be connected to the one or more processors 102 and 202 and transmit and receive radio signals. For example, the one or more processors 102 and 202 may perform control such that the one or

more transceivers

106 and 206 may transmit user data, control information, or radio signals to one or more other devices. The one or more processors 102 and 202 may perform control such that the one or

more transceivers

106 and 206 may receive user data, control information, or radio signals from one or more other devices. The one or

more transceivers

106 and 206 may be connected to the one or

more antennas

108 and 208 and the one or

more transceivers

106 and 206 may be configured to transmit and receive user data, control information and/or radio signals/channels mentioned in the description, functions, procedures, proposals, methods and/or operational flow diagrams disclosed in this document through the one or

more antennas

108 and 208. In this document, the one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). The one or

more transceivers

106 and 206 may convert received radio signals/channels, etc. from RF band signals to baseband signals for processing received user data, control information, radio signals/channels, etc. using the one or more processors 102 and 202. The one or

more transceivers

106 and 206 may convert user data, control information, radio signals/channels, etc. processed using the one or more processors 102 and 202 from baseband signals to RF band signals. To this end, the one or

more transceivers

106 and 206 may comprise (analog) oscillators and/or filters.

9. Examples of wireless devices to which the disclosure applies

Fig. 34 illustrates another example of a wireless device applicable to the present disclosure. The wireless device may be implemented in various forms depending on use cases/services (see fig. 32).

Referring to fig. 34,

wireless devices

100 and 200 may correspond to

wireless devices

100 and 200 of fig. 33 and include various elements, components, units, and/or modules. For example, each of the

wireless devices

100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and additional components 140. The communication unit may include a communication circuit 112 and a transceiver 114. For example, the communication circuitry 112 may include the one or more processors 102 and 202 and/or the one or

more memories

104 and 204 of fig. 33. For example, transceiver 114 may include the one or

more transceivers

106 and 206 and/or the one or

more antennas

108 and 208 of fig. 33. The control unit 120 is electrically connected to the communication unit 110, the memory 130, and the additional components 140 and controls the overall operation of each wireless device. For example, the control unit 120 may control the electrical/mechanical operation of each wireless device based on programs/codes/commands/information stored in the memory unit 130. The control unit 120 may transmit information stored in the memory unit 130 to the outside (e.g., other communication devices) through the communication unit 110 through a wireless/wired interface. In addition, the control unit 120 may store information received from the outside (e.g., other communication devices) via the communication unit 110 through a wireless/wired interface in the memory unit 130.

The add-on component 140 can vary depending on the type of wireless device. For example, the add-on component 140 may include at least one of a power supply unit/battery, an input/output (I/O) unit, a drive unit, and a computing unit. A wireless device may be implemented in the form of: robot 100a (fig. 32), vehicles 100b-1 and 100b-2 (fig. 32), XR device 100c (fig. 32), handheld device 100d (fig. 32), household appliance 100e (fig. 32), IoT device 100f (fig. 32), digital broadcast terminal, hologram device, public safety device, MTC device, medicine device, financial technology device (or financial device), security device, climate/environmental device, AI server/device 400 (fig. 32), base station 200 (fig. 32), network node, and the like. However, the wireless device is not limited thereto. Wireless devices may be used in mobile or fixed places depending on use cases/services.

In fig. 34, all of the various elements, components, units/sections, and/or modules in the

wireless devices

100 and 200 may be connected to each other through a wired interface or at least a part thereof may be wirelessly connected through the communication unit 110. For example, in each of the

wireless devices

100 and 200, the control unit 120 and the communication unit 110 may be connected by a wire, and the control unit 120 and the first unit (e.g., 130, 140) may be wirelessly connected by the communication unit 110. Each element, component, unit/portion, and/or module of

wireless devices

100 and 200 may also include one or more elements. For example, the control unit 120 may be implemented with a set of one or more processors. In one example, the control unit 120 may be implemented with a communication control processor, an application processor, an Electronic Control Unit (ECU), a graphics processing unit, and a memory control processor. In another example, memory 130 may be implemented with Random Access Memory (RAM), Dynamic RAM (DRAM), Read Only Memory (ROM), flash memory, volatile memory, non-volatile memory, and/or any combination thereof.

Hereinafter, an implementation example of fig. 34 will be described in detail with reference to the accompanying drawings.

10. Examples of Mobile devices to which the disclosure is applied

Fig. 35 illustrates a handheld device applicable to the present disclosure. The handheld device may include a smartphone, a smart tablet, a wearable device (e.g., a smart watch or smart glasses), or a portable computer (e.g., a laptop). A handheld device may be referred to as a Mobile Station (MS), a User Terminal (UT), a mobile subscriber station (MSs), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or a Wireless Terminal (WT).

Referring to fig. 35, the handheld device 100 may include an antenna unit 108, a communication unit 110, a control unit 120, a memory unit 130, a power supply unit 140a, an interface unit 140b, and an I/O unit 140 c. The antenna unit 108 may be implemented as part of the communication unit 110. The blocks 110 to 130/140a to 140c correspond to the blocks 110 to 130/140 of fig. 34, respectively.

The communication unit 110 may transmit and receive signals (e.g., data and control signals) to and from other wireless devices and/or base stations. The control unit 120 may perform various operations by controlling the components of the handheld device 100. The control unit 120 may include an Application Processor (AP). The memory unit 130 may store data/parameters/programs/codes/commands required to drive the handheld device 100. The memory unit 130 may store input/output data/information. The power supply unit 140a may supply power to the handheld device 100 and include a wired/wireless charging circuit, a battery, and the like. The interface unit 140b may support connections between the handheld device 100 and other external devices. The interface unit 140b may include various ports (e.g., audio I/O ports, video I/O ports, etc.) for connection with external devices. The I/O unit 140c may input or output video information/signals, audio information/signals, data, and/or information input by a user. The I/O unit 140c may include a camera, a microphone, a user input unit, a display unit 140d, a speaker, and/or a haptic module.

For example, in data communication, the I/O unit 140c may obtain information/signals (e.g., touch, text, voice, image, video, etc.) input by a user and may store the obtained information/signals in the memory unit 130. The communication unit 110 may convert the information/signals stored in the memory unit 130 into radio signals and transmit the converted radio signals directly to another wireless device or to a base station. The communication unit 110 may receive a radio signal from another wireless device or a base station and restore the received radio signal to original information/signal. The recovered information/signals may be stored in the memory unit 130 and output in various forms (e.g., text, voice, images, video, haptic, etc.) through the I/O unit 140 c.

11. Examples of vehicles or autonomous vehicles to which the disclosure is applied

Fig. 36 illustrates a vehicle or autonomous driving vehicle applicable to the present disclosure. The vehicle or autonomous driving vehicle may be implemented as a mobile robot, an automobile, a train, a manned/unmanned Aerial Vehicle (AV), a ship, or the like.

Referring to fig. 36, a vehicle or autonomous driving vehicle 100 may include an antenna unit 108, a communication unit 110, a control unit 120, a driving unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140 d. The antenna unit 108 may be configured as part of the communication unit 110. Blocks 110/130/140a through 140d respectively correspond to block 110/130/140 of fig. 34.

The communication unit 110 may transmit and receive signals (e.g., data and control signals) to and from external devices such as other vehicles, base stations (e.g., gnbs and wayside units), and servers. The control unit 120 may perform various operations by controlling elements of the vehicle or autonomous driving vehicle 100. The control unit 120 may include an Electronic Control Unit (ECU). The drive unit 140a may cause the vehicle or the autonomous driving vehicle 100 to drive on the road. The driving unit 140a may include an engine, a motor, a powertrain, wheels, a brake, a steering device, and the like. The power supply unit 140b may supply power to the vehicle or the autonomous driving vehicle 100 and include a wired/wireless charging circuit, a battery, and the like. The sensor unit 140c may acquire a vehicle state, surrounding environment information, user information, and the like. The sensor unit 140c may include an Inertial Measurement Unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a grade sensor, a weight sensor, a heading sensor, a positioning module, a vehicle forward/backward sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illumination sensor, a pedal position sensor, and the like. The autonomous driving unit 140d may implement the following techniques: techniques for maintaining a lane on which a vehicle is driving; techniques for automatically adjusting speed (such as adaptive cruise control); techniques for autonomously driving along a determined path; and a technique of automatically setting a route to travel when a destination is set.

For example, the communication unit 110 may receive map data, traffic information data, and the like from an external server. The autonomous driving unit 140d may generate an autonomous driving path and a driving plan from the obtained data. Control unit 120 may control drive unit 140a such that the vehicle or autonomous driving vehicle 100 may move along an autonomous driving path according to a driving plan (e.g., speed/direction control). During autonomous driving, the communication unit 110 may periodically acquire the latest traffic information data from an external server and may acquire the surrounding traffic information data from neighboring vehicles. During autonomous driving, the sensor unit 140c may obtain vehicle status and/or ambient environment information. The autonomous driving unit 140d may update the autonomous driving path and the driving plan based on the newly obtained data/information. The communication unit 110 may send information about the vehicle position, autonomous driving path, and/or driving plan to an external server. The external server may predict traffic information data using AI technology or the like based on information collected from the vehicle or the autonomously driven vehicle and provide the predicted traffic information data to the vehicle or the autonomously driven vehicle.

12. Examples of AR/VR and vehicle to which the disclosure is applied

Fig. 37 illustrates a carrier applicable to the present disclosure. The vehicle may be implemented as other means of transportation such as trains, airplanes, ships, etc.

Referring to fig. 37, vehicle 100 may include a communication unit 110, a control unit 120, a memory unit 130, an I/O unit 140a, and a positioning unit 140 b. The blocks 110 to 130/140a to 140c correspond to the blocks 110 to 130/140 of fig. 34, respectively. The communication unit 110 may transmit and receive signals (e.g., data and control signals) to and from external devices such as a base station or other vehicles.

The control unit 120 may perform various operations by controlling components of the vehicle 100. Memory unit 130 may store data/parameters/programs/codes/commands for supporting various functions of vehicle 100. The I/O unit 140a may output the AR/VR object based on the information within the memory unit 130. I/O unit 140a may include a HUD. Positioning unit 140b may acquire information about the orientation of vehicle 100. The orientation information may include information about an absolute orientation, an orientation on the driving lane, an acceleration, and a relative orientation of a neighboring vehicle with respect to the vehicle 100. The positioning unit 140b may include a Global Positioning System (GPS) and various sensors.

For example, the communication unit 110 of the vehicle 100 may receive map information and traffic information from an external server and store the received information in the memory unit 130. Positioning unit 140b may obtain vehicle position information from GPS and various sensors and store the obtained information in memory unit 130. The control unit 120 may generate a virtual object based on the map information, the traffic information, and the vehicle orientation information, and the I/O unit 140a may display the generated virtual object on windows (1410 and 1420) in the vehicle. The control unit 120 may determine whether the vehicle 100 is traveling normally on the traveling lane based on the vehicle orientation information. If the vehicle 100 irregularly leaves the driving lane, the control unit 120 may display a warning on a window in the vehicle through the I/O unit 140 a. Further, the control unit 120 may broadcast a warning message about irregular driving to neighboring vehicles through the communication unit 110. In some cases, the control unit 120 may send vehicle orientation information and information about an abnormality in driving/vehicle to the relevant department.

The present disclosure may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the present disclosure. The above implementations are therefore to be construed in all aspects as illustrative and not restrictive. The scope of the disclosure should be determined by the appended claims and their legal equivalents, rather than by the description above, and all changes that come within the meaning and range of equivalency of the appended claims are intended to be embraced therein. It will be apparent to those skilled in the art that claims that are not explicitly cited within each other in the appended claims may be presented in combination as an implementation of the present disclosure or included as new claims by subsequent amendment after the application is filed.

INDUSTRIAL APPLICABILITY

Implementations of the present disclosure may be applied to various wireless access systems including 3GPP and/or 3GPP 2. Implementations of the present disclosure are also applicable not only to various wireless access systems, but also to all technical fields in which wireless access systems find their application. In addition, the proposed method may be applied to a millimeter wave communication system based on a super high frequency band.

Additionally, implementations of the present disclosure may also be applied to various applications such as autonomous driving vehicles, drones, and the like.

Claims

1. A method for operating a User Equipment (UE) in a wireless communication system supporting narrowband internet of things (NB-IoT), the method comprising:

determining a time period for receiving a Narrowband Reference Signal (NRS) on a non-anchor carrier for paging; and

receiving the NRS for the period of time,

wherein the time period is determined based on a specific Paging Occasion (PO) among a plurality of POs related to the UE.

2. The method of claim 1, wherein the particular PO is a PO having an odd subframe number among the plurality of POs.

3. The method of claim 1, wherein the particular PO is a PO having an odd subframe number and an even System Frame Number (SFN) among the plurality of POs.

4. The method of claim 1, wherein the particular PO is a PO having an even subframe number and an odd System Frame Number (SFN) among the plurality of POs.

5. The method according to claim 1, wherein the specific PO is a PO in which a remainder of division of S by R is equal to a remainder of division of Q +1 by 2 among the POs,

wherein S is a System Frame Number (SFN) of the PO,

wherein R is a value preconfigured by higher layer signals, and

wherein Q is a subframe number of the PO.

6. The method of claim 5, wherein R is determined based on a ratio between a number of frames and a number of POs.

7. The method of claim 5, wherein the first and second light sources are selected from the group consisting of,

wherein R is 2 in the case where the number of POs in one frame is greater than or equal to 2, and

wherein, in the case where the number of POs in one frame is less than 2, R is 1.

8. The method according to claim 1, wherein the specific PO is a PO in which a remainder of division of S by R is equal to a remainder of division of Q + a by 2 among the POs,

wherein S is a System Frame Number (SFN) of the PO,

wherein R is a value pre-configured by a higher layer signal,

wherein Q is a subframe number of the PO, and

wherein a is 0 or 1.

9. The method of claim 8, wherein the first and second light sources are selected from the group consisting of,

wherein in the case where the number of POs in one frame is less than 1, a is determined to be 1, and

wherein a is determined to be 0 or 1 based on the SFN of the specific PO in the case that the number of POs in one frame is greater than 1.

10. The method of claim 1, wherein the specific PO is a PO of subframe number 9 among the plurality of POs.

11. The method of claim 1, wherein the receiving of the NRS during the time period is performed independently of a page transmission.

12. A User Equipment (UE) in a wireless communication system supporting narrowband internet of things (NB-IoT), the UE comprising:

at least one Radio Frequency (RF) module;

at least one processor; and

at least one memory operatively connected to the at least one processor and configured to store instructions executable by the at least one processor to perform certain operations including:

receiving the NRS for the period of time,

wherein the time period is determined based on a specific Paging Occasion (PO) among a plurality of POs related to the UE, and

wherein reception of the NRS within the time period is independent of the presence of a paging transmission.

13. The UE of claim 12, wherein the particular PO is a PO of the plurality of POs in which a remainder of S divided by R is equal to a remainder of Q +1 divided by 2,

wherein S is a System Frame Number (SFN) of the PO,

wherein R is a value preconfigured by higher layer signals, and

wherein Q is a subframe number of the PO.

14. The UE of claim 12, wherein the UE is in communication with at least one of: a mobile terminal, a network, or an autonomous driving vehicle other than the vehicle that includes the UE.

15. A base station for transmitting downlink signals in a wireless communication system supporting narrowband internet of things (NB-IoT), the base station comprising:

at least one Radio Frequency (RF) module;

at least one processor; and

at least one memory operatively connected to the at least one processor and configured to store instructions executable by the at least one processor to perform certain operations including transmitting a Narrowband Reference Signal (NRS) on a non-anchor carrier for paging to a User Equipment (UE) for a certain period of time,

wherein the specific time period is determined based on a specific Paging Occasion (PO) among a plurality of POs related to the UE;

wherein the transmission of the NRS within the certain time period is independent of the presence of a paging transmission.

16. The base station according to claim 15, wherein the specific PO is a PO in which a remainder of division of S by R is equal to a remainder of division of Q +1 by 2 among the POs,

wherein S is a System Frame Number (SFN) of the PO,

wherein R is a value preconfigured by higher layer signals, and

wherein Q is a subframe number of the PO.